Firstly I'm the founder and owner of LandlordMax Software (
http://www.LandlordMax.com), a property management software company. The company has been in business for over 10 years now and has been growing quite well over the years:
http://www.followsteph.com/2013/08/07/landlordmax-2012-2013-...The real reason you don't see many new flashy new trendy apps is that creating real estate related generally a hard problem to solve. Sure it's simple to create a simple accounting system that's like personal accounting solution, but when it comes to managing properties you need a lot more than that!! And even the accounting system is not that simple. You need to link the properties to buildings, tenants, manage late rents, fees, and so on. Then you also need to realize that many payments will be late. Some payments may be spread over multiple properties, such as things like computer hardware where the costs are spread over many properties. This doesn't even include security deposits which is a special class of accounting data.
Then you need some pretty extensive reporting features. You can't assume just one property owner, so you need to deal with that. Also when it comes to taxes, tenants, etc. you'll need a significant number of different reports to support this. You'll basically need a pretty extensive list of reports as a minimum.
Now we haven't even started talking about managing leases and rentals. Basically what tenants live where, which units will be vacant, which units have leases, which leases are coming due. What about security deposits (also related to accounting but a special case).
From there you need to manage tracking workorders, regular maintenance that needs to be done, and everything else that comes with managing properties. Lists of vendors, which vendors work on which properties. This can be especially tricky if for example you sometimes use say a specific plumber for some properties and another for other properties.
And of course I haven't even started to talk about managing the tenants themselves. Keeping track for example of when a tenant was given a notice, was told to turn down the music, and so on. Then you also need to track all kinds of info on the tenants, things like employers, contact numbers, references, you name it.
And then there's the tenants themselves. Not all tenants are people, some are companies. Properties are not all buildings. There are different types of tenants and properties. And the software needs to be smart enough to not only present the user with the proper screens and data (and store it all), but also have the proper interactions between these different data types. And of course be able to run reports on them. So you can't just say multiplex buildings go in one table because if you do this good luck creating a report grouped by building (single and multi) for a single property owner (as well as per unit for a building), which is something all property management companies will require as a report for their own clients.
But there's more. You need all kinds of additional functionality and integrations. For example most property owners want to integrate their systems with emails. They may want to incorporate images of the units pre and post, for legal purposes. Then what about documents such as leases and so on, you need a file management system.
And then there's all the logic and validation. It's not just foreign keys and relationship tables. Some data may be somewhat cyclical. And everything of course needs to be performant.
In all this you also have to remember that most users are not technical, so you need to anticipate this and prepare accordingly.
And we haven't even talked about security and other issues such as just plain old usability. So that also has to be taken into consideration.
Then there's whitelabelling. A property management company doesn't want records to come from the software company, it has to have their own logo/letterhead and so on.
Beyond that you'll eventually have to start dealing with large amounts of data. Most customers who use software for example will have more than a handful of tenants and buildings. Possibly hundreds. So how do you present a drop down menu to select tenants? It's easy for say under 50 tenants. But what about someone who has 200 rentals? Now what if they have 5 years of data on top of that. It could be a 1000 tenants in their database. And in case you're wondering you can't really archive data because of the nature of the beast: http://www.followsteph.com/2009/02/09/sometimes-simple-thing... So for us that meant we had to create special custom drop down menus that have custom sorting and coloring when prsenting tenants, so that all current tenants appear at the top alphabetically before the older non-current tenants. This might seem like a small details, but what you quickly learn is that there are a LOT of them!!
Basically creating a property management software solution is a complex task, and it's not something you can just create in a weekend or month. The minimum viable product is quite large. In the years we've been in business I've seen a lot of companies come and go. Most barely last more than a year or two. There's a lot of data, situations, and features that are required to manage properties.
And that's one of the benefits of being in this less sexy industry than say social media, at least once you get your foothold. It takes at least 2-3 years to get a good product going. Also because there are so many companies that disappear quickly, many customers are only interested in purchasing from companies that have been in business for a while. Another bias in your favor.
And this is why you don't see many people from here jump into it very often. It's not something you can do as quickly or easily, there is a pretty high barrier to entry. It might seem simple, but it's not. And that's an advantage with time.
Now this isn't to say that old solutions shouldn't improve, there is room. And someone like us has definitely disrupted the industry since we started. But please realize that a LOT of time, effort, and money is spent on implementing the functionality that you can't just re-skin your app every 2-3 years because it's trendy. That's not where the value is, it's in helping people effectively manage their properties!
PS: I'll also shortly discuss why rental payments is also similar in another comment.
In any case, please feel free to ask me questions and I'll try to respond. A mini AMA if you will ;)