Consumer culture issues aside, there's also a big point that DRAM prices have been stagnating the last few years (from the low they hit around 2011/2012) as they tend to end up doing once in a while for one reason or another, so a well-stocked system configured 5 years ago might be MORE expensive to build or upgrade now than it was back then. (aside from second-hand parts, and even then RAM prices -for current-ish DDR3 1333/1600/1866- haven't been particularly cheap)
And aside from gaming, the only real benefit from buying/buyilding a totally new system now compared to 5 years ago in the low-to-mid-range cost/performance category would be power consumption ... unless you want an AMD CPU/APU, in which case you're probably not going to gain much performance/watt efficiency there either. (actually, if you put together a low power Intel based system around 2011/2012, you probably wouldn't gain all that much now either)
And the gaming end is a separate issue too, though on the tweak-happy user on a budget, you also won't gain much from a total system upgrade, especially looking at only new parts. (CPU upgrading an older AM3+ compatible or LGA-1155 based system might make sense depending on what your existing setup is -especially since the old Phenoms/Athlons lack some newer multimedia instructions even if a game doesn't gain much from the 6 or 8 integer cores- and a second hand i5 or i7 might be a good upgrade on a slower -or non overclockable- i5 or i3 or Pentium Dual Core -which was a solid budget gaming option back in 2012) GPU upgrades are obviously the more typically meaninful option, though.
Also a shame e-waste is the main (or only) option for dealing with old components/systems for most people. Trade-in or donation to used PC warehouses/dealers is a lot nicer, or just local listing sales (Craigslist/etc). Not to mention the level of waste/incompetence (on top of poor working conditions) involved in most e-waste recycling operations. Old game consoles are more likely to end up donated to thrift stores at least (and old home computers that haven't ended up trashed yet -but not owned by someone savvy enough to sell them themselves) and a lot of thrift stores have developed online stores and auctions with less and less ignorant listings of more popular old tech (and tech in general). But on the PC end, anything bigger than a graphics card or maybe motherboard tends to be harder to sell online. (OTOH, as various organizations and people get more savvy, the super cheap deals also start disappearing)
I wonder if overseas PC scrappers have gotten wise of some of that too and started sorting out stuff useful for resale rather than scrapping. For that matter, given the performance envelope demand in some overseas countries, I'd think there'd be big potential business for sorting and refurbishing discarded components rather than totally scrapping it. (for vaguely new-ish and general-purpose usable stuff, not VINTAGE )
Monitors are just a pain to deal with though ... heavy and/or fragile (be it CRT or LCD) and expensive to ship. (pretty much only good for buying/selling/donating locally -including the off-chance you do have a warehouse operation in your area)
And granted, overseas scrapping operations wouldn't even be economical to use if it wasn't for a ton of other economic binds, exceptions, and general backwardness/disparity (and lack of regulation) that makes shipping stuff back and forth super-long distances actually worth the waste of fuel, time and other resources. (compared to local recycling, reprocessing, refurbishing, etc) But any more on that would tend to get pretty political. 😜
And just some fun little anecdotes but: until I think 3 years ago, my grandpa was still using the old PIII-733 system for day to day stuff (mostly email and office and some photo/video use) that Dad had put together for him some 10 years prior which itself was a Compaq workstation Dad got from IBM's discard pile when he worked there. (oddball RDRAM based system too, upgraded from 256 to 640 MB late in life before it finally got retired) And Grandma's still using her 2008 HP Pavilion 9700 (I'd probably still be using mine for day to day stuff if the HDD hadn't crashed when the system fell off my desk -still working with a new drive, but I switched to a desktop build back in 2013 for most stuff)