Beg to differ.I want to future-proof my next Apple Mac because they are expensive machines. Overpriced upgrade options is bad enough. Not letting anyone ever upgrade RAM or SSD on their machines again is a shame.
I've been through those exercises a few times both for stationary and Thinkpads, and the numbers don't add up.
Basically what you do is debottlenecking the computer. Which means whenever you carry out an upgrade of the component constraining your work, you remove a bottleneck. That means that another component becomes the bottleneck, and then the next one and the next one. For instance a juicy graphics card with a now lame CPU or a motherboard for that matter.
Meanwhile, newer computers have progressed, thus when you replace a component it is one inferior to later tech, and as the vendors becomes fewer and and less components are available the prices goes up. If a computer lasts for say 8 years and you upgrade it after 4 you'll have to "write off" the upgrade costs within a shorter period. In addition to that, you are stuck with the parts you removed and nobody wants it.
Assuming long term economical Mac ownership with decent performance is the objective, I'd rather go 2nd hand, for instance 2 years old with the spec you need for the planned duration of ownership, and keep it for whatever makes sense - 2-4 years, then get another 2nd hand as an upgrade for what you need THEN, and sell off the one you are replacing. You will have great and quite recent hardware matching your needs at any given time, and very sound annual costs of ownership.
If you spec for the future (no one knows what's up next anyway) you pay a lot for stuff you don't need. Better save the cash until you need a different spec.
One can do the same thing with iPhones as they get updates for a long time. Buy 1-2 years old just around fresh releases by Apple, and keep them for whatever makes sense.
I bought a new iPad 12.9 Pro cellular 2020 in 2021 at clearance discount, and sold it 14 months later for the exact same amount. I lost 40 USD (the cover) but nothing on the iPad and the pen. 3 USD a month for that pad is fairly neat.