For some perspective: Computer Shopper 1993 GW2K 386SX at $1300. Today that is $2800. That $699 Mac is getting you a machine that would have been a TOP500 supercomputer in the 90s.

And your credit card has a more powerful computer than the Apollo lunar lander.

But software development (for both OS and applications) is continuing in parallel with hardware improvements, so there's a strong implicit demand of you to also continue upgrading, at least if you need to interoperate with any other computer in the world.

If my Grandmother had wheels she would have been a bike. Yes, things change over time. I cringe to think of what some of the original 42" flat screen displays cost relative to the huge (much better looking) OLED panels of today.

That's about 6 years. Plenty enough for a laptop that's not upgradeable.