So what if it is money grabbing? The purpose of a corporation is to make as much money as it can.
Today, an iPhone 15 does everything it did when you bought it. Nobody is forcing you to buy a new phone and spend that money. Just don't do it! I generally wait 3 years between phones. I didn't this time only because I expect to be dead before the next one comes out.
A new device having more features than your current one hardly makes yours obsolete. The 15 will be a perfectly good and supported phone for MANY years. You could EASILY be just fine using it another 4 years, if you can resist the urge to feel unhappy because you don't have the latest and greatest.
Hell, my MacBook Pro is from 2012. Coming up on 13 years old! It works just great! My 2007 Jeep and 2009 Yamaha TMAX (motorcycle) are also old but just fine.
It's all about mental attitude. Choose to be unhappy with your current phone, or not. It's up to you, not Apple.