I see what you're saying, but I also think it's actually a mark in Linux' favor that is continues to run so well on older or underpowered hardware. It's how I really got into it, being broke and able to eke out years more life on older computers when I could ill afford upgrades. These days, I'm happy that I can get off the upgrade treadmill for longer. The most demanding games I've installed are the Final Fantasy I-VI Pixel Remasters and Grandia. I'm not a programmer, don't have to render graphical stuff for work, etc, so it's pretty great that I don't have to worry about my budget desktop being unusable in 4 years because the OS devs have made it a practical impossibility to run on older hardware. I've got 32GB of RAM, and my biggest threat to usability is leaving Firefox running with a ton of open tabs for weeks on end, which can conveniently be solved by closing Firefox and watching my RAM use plummet.
Not everyone is going to be a gamer, graphics designer or programmer that really needs the latest and greatest in hardware. In fact, I'd wager the majority of people won't notice an improvement outside of a few cases. Upgrading from an HDD to an SSD, <16GB of RAM to >16GB of RAM and from an older graphics card to a newer one that supports 4K are pretty easy differences to note in normal use. Those aside, I think most people would be hard-pressed to identify an objective difference in the quality of their browsing and word processing experiences. Depending on how flexible people are with adapting to different workflows, even those could be minimized, to an extent. I have a desktop I bought second hand twenty years ago that served as my main computer into and beyond my initial forays in university. It has a whopping two cores, and I think I might have managed to get 16GB of RAM into it. It'd probably suck for web browsing and wouldn't be terribly efficient for power use, but I bet you if I reinstalled things, it would work just fine for serving up my music library via mpd, playing it with ncmpcpp and writing term papers in Auctex, same as it did back then. Even if I put an older version of Windows on it like Windows 7, I bet it would struggle to run those same programs on top of the base OS. That's legitimately impressive, when you think about it.