I understand where you're coming from, but I've had over a decade of experience owning and managing both personal and rental real estate so I wanted to chime in.
> They were right if you ever want to have a family.
Not entirely. "Ever" is a really strong word. If you want to have a family later in life, that should not prevent you from living in places you'd like to experience. You will likely regret being so cautious at the exact time in your life when you had the least reason to be so.
> You are building no equity in rent
If you are saving a dramatic amount of money per month and putting that money away in savings or another investment vehicle, then I would argue that you very much are. People underestimate how little "equity" they actually build up when they didn't happen to buy before or early in a real estate bubble. In reality, the closing costs of acquiring the property, maintenance, insurance, and property taxes, and the (optional but likely) 6% sales commission the realtor takes when you decide to sell all add up and chip away at effective equity. True, equity will eventually outpace these costs, but the time that takes is a function of how well the market is doing and other externalities.
There's also a cost of liquidity. $10,000 sitting in a bank account at 0.1% is arguably worth more than $10,000 of equity in a house that might take 3 months to sell.
All of this means that unless you know you're going to buy a place and stay put for a while, you'd probably be better taking the cost difference and building "liquid equity" that you can use later.
> so you will essentially have to leave and start over somewhere else to have kids.
True, but that may be a complete non-problem depending on your disposition. Personally, I don't get attached to places. They're just boxes with soft places to sleep. Relationships make it a home. In my case, in the unlikely event I decided to start a family, I could buy a house relatively close to the apartment I live in now (if I so desired). I wouldn't call that starting over. By the way, I'd be able to buy that house because I was able to save a metric crap-ton of cash while living on next to nothing with cheap rent.
> Your story is fine as long as it ends with you being single and alone without any real assets.
As I believe I have demonstrated, you have no justification for this statement; none whatsoever. It's simply not the case that a person who choses to spend one part of his or her life saving money living with roommates in a fun town will be forever "trapped" by that choice.
Also, you might not have intended it this way, but that statement was mean-spirited.