Great question. Appreciate the interest.
I can only speak from my perspective as an employee, not the whole company. It is something I've thought about. I will also ask the CEO/founder or other leaders to weigh in.
Many devs care about open source when they are evaluating a solution, but many really want "free as in beer". They want to try a product without getting out the credit card or engaging with sales. We cater to the latter category, which wants to understand the product quality without talking to any sales people.
Some of these folks use our community product for their production needs, which is perfectly fine. We have people running FusionAuth in production with 1000s of tenants or 10000+ applications. (I always say they "pay" us by filing bug reports, giving feedback and voting on feature requests.)
But some decide they want to pay us for hosting, support or advanced features. Those choices help us build a business.
Devs, and especially buyers, are interested in sustainability of a product they are going to integrate into their system. An auth provider isn't a javascript widget that you can easily drop in or remove from your system. It embeds in your system, even if you stick to a standard like OIDC, and is difficult to switch from, especially at scale. You want to be sure the company and product is going to stick around. (If you want to make sure you can run the product even if everyone at FusionAuth wins the lottery, we do offer source code escrow for a price, but haven't had anyone take us up on it.)
FusionAuth is a profitable company (we did recently raise a round to accelerate growth, you can read more about that here [0]). Open source companies often have a hard time meeting the profit goals of the market or investors. This is a known issue and often results in relicensing or changing the rules, as we've seen with Hashicorp[1] and Elastic[2]. This switcheroo can cause issues, confusion, and ill-will; FusionAuth's licensing avoids that.
FusionAuth also develops in the open[3]. This open development process gives us another common benefit people get from OSS--community feedback.
Also, I don't want to throw shade at Ory and Zitadel, since I have no idea about their finances (apart from a brief look at Crunchbase, which shows they've raised 22.5M[4] and 2.5M[5] respectively). I hope they're building sustainable businesses, but selling closed source software is a sure route to a profitable business that has built many big companies (including in the auth space, such as Okta or Auth0). Again, this is not FUD (or at least I don't intend it to be!), just an honest assessment at the difficulties of making money in open source dev tools [6].
We also compete on features, support and documentation. Again, I can't speak to Ory or Zitadel; they look nice, but I haven't built anything with them, so it is hard for me to know how good they are. I do know that we have had many clients appreciate of those aspects of our product.
To sum up:
* FusionAuth has a free option, which helps reduce friction and gives some of the benefits of OSS. The open process and escrow also give some of the benefits of OSS.
* Some devs and buyers care about business sustainability, especially when integrating a tool deeply into their application. FusionAuth will never have to worry about relicensing a version because AWS is eating our SaaS revenue stream, for example.
* We offer great support, documentation and intricate auth features at a reasonable price.
Hope this helps.
0: https://fusionauth.io/blog/fusionauth-and-updata
1: https://www.hashicorp.com/license-faq
2: https://www.elastic.co/pricing/faq/licensing
3: https://github.com/FusionAuth/fusionauth-issues/issues/
4: https://www.crunchbase.com/organization/ory/company_overview...
5: https://www.crunchbase.com/organization/zitadel
6: I wrote about this a few years ago on my personal blog: https://www.mooreds.com/wordpress/archives/3438