What games are you looking at playing on the Mac?

Overall, and I mean this with the greatest respect, if you've got money to burn they go for the best you can (we all have to do it sometimes), otherwise complete overkill and your "outdated" timescale argument is completely flawed.

I've been using both WinTel and Mac devices since 2006, the latter mostly focused on photo and video editing. I've the entry spec MacBook Pro 13 (2011/2012 I think) which my daughter now has as her device), and a iMac 27" that I use for editing (again about 10 years old).

As long as they're looked after they will last.

In terms of performance we're at a point where 90% of devices are powerful enough to run 95% of software. It's only when you get to the realms of pushing 4k across multiple monitors or pushing hi rez VR that system power is likely to become an issue. That often comes down to GPU. That isn't often an issue you'll have on a Mac.

The thing to keep in mind is Mac generally offers OSX support for 7 - 10 years. That is more likely to cause you an issue more than specification as its based on year of manufacturing. Both my Mac devices can't use the most current OSX, and some of the software updates for Adobe Lightroom can't be installed. The existing version runs flawlessly though.

I'll add that I've also had a MacBook Air and had exactly the same experience.

So, in summary, again if you've got money to burn get the best device you can but it'll likely, 100% be complete overkill. With the new chips you could probably get an entry or entry +1 MacBook Air, MBP or any flavour and you'll happily be using it until its software updates expire.