This has been the consequence of increasingly cheap money and investor money having nowhere to go after the real estate crash in 2008. To be fair, if money is basically free then it does make sense to grow without worrying about a profit. If you've had an entire career without every having to worry about more investor money coming it, it would start to seem wasteful to not spend it all.
But that's why these current economic conditions have me very worried: money can't be cheap anymore. If interest rates continue to rise we'll see a massive contraction in tech. First it will be the smaller, direct to consumer startups, then it will be all of the companies that have those startups as a non-trivial portion of their revenue.
There's a difference between 'not profitable' and 'losing money.'
The issue is that many of these companies have never demonstrated that if they want to they can be profitable. The big assumption in these growth models is that there is a point where you can just magically flip that profit switch.
For example if I run a lemonade stand where I spend $3 to make a $1 glass of lemonade, even if I am able to use investor capital to keep growing my lemonade stand to be the only lemonade stand in town, or even the world, it's not clear that I can survive if I'm forced to make a profit.
Seriously, when did it become normal in capitalism that you should not prove that your business can make money? That there a customers willing to pay for your product? That the promise of future maybe profit sells better than actual profit now? This is insane.