I have a newish MBP from 2018. It’s still fast as hell and reliable. I can’t upgrade the OS because it is not supported. I don’t use Safari, but I’m sure there are people out there using a perfectly fine computer that Apple has dropped support for.
https://support.apple.com/en-sg/HT213264
As far as I can see, the only possibility for buying a new MacBook Pro in 2018 that can’t run Ventura is if you bought the MacBook Pro Retina (Mid 2015) model, which wasn’t discontinued until mid-2018. All the older MacBook Pros that can’t run Ventura were discontinued in 2017 or earlier:
https://en.wikipedia.org/wiki/List_of_Mac_models#2015
I think Ventura not supporting a model released more than seven years beforehand is a reasonable cut-off point. But if there are people who want to use an older model with a newer browser, they can use Firefox or Chrome.
Some kid somewhere digs up a rock under gunpoint and we're expected to throw it out as soon as something shinier comes along, disgusting. It's because of companies acting like this we need regulations on support and right to repair.