I think this has to be the number one misunderstanding for developers.
Yes, SSD in terms of throughput or IOPs has gone up by 100 to 10000x. vCPU performance per dollar has gone up by 20 - 50x. We went from 45/32nm to now 5nm/3nm, and much higher IPC.
But RAM price hasn't gotten anywhere near the same fall as CPU or SSD. It may have gotten a lot faster, you may be even getting to stick lots of memory with higher density chip and channels went from dual to 8 or 12. But if you look at the DRAM Spot price since 2008 to 2022, you will see the lowest DRAM price has been the same at around $2.8/GB for three times. As the DRAM price goes in cycle with $8 / $6 per GB in between this same period. i.e Had you bought DRAM at its lowest point or its highest point during the past ~15 years your DRAM would have cost roughly the same plus or minus 10-20% ignoring inflation.
It was only until Mid 2022 it finally broke through the $2.8/GB barrier and collapse close to $1/GB before settling on ~ $2/GB for DDR5.
Yes you can now get 4TB RAM on a server. But it doesn't mean DRAM are super cheap. Developers on average or for those in big Tech are now earning way more than they were in 2010. Which makes them think RAM has gotten a lot more affordable. In reality even in the lowest point over past 15 years you only get at best slightly more than 2x reduction in DRAM price. And we will likely see DRAM price shot up again in a year or two.