The quote is 640K and Gates said it's apocryphal.
Pick most any hardware specification and software bloat will exceed it at some point. Game developers learned much from Crysis marketing. The idea has been to get used as a benchmark by all the review sites by going further than other games in terms of hardware demands. Since there is a marketing incentive to push the limits of hardware one can rest assured that RAM bloat will be an issue, likely before the games become advanced enough to truly need all that RAM. Do an EA and claim that the game has special secret tech that is really really advanced (remember SimCity 5 having to be always-online because of all the super-duper calculations EA claimed were being done by its supercomputers?).
It wasn't very long ago when 8 GB of RAM was considered plenty for gaming. Prior to that it was 4 GB. It doesn't seem really so long ago that the 1.5 GB buffer of the normal GTX 580 seemed like plenty.
Gates understood that hardware is always advancing. The only people who should take that quotation seriously are those who don't realize that tech insiders are highly-familiar with the way hardware is always advancing. No software or hardware guru would ever claim a certain amount of RAM is enough for anyone going forward. Claiming it's enough for them at that point in time and in the near future is another matter.
I mostly agree, but 8GB has not been considered plenty for some time. In the Sandy Bridge era, 8 years ago, 16GB was the recommended amount. System ram needs haven't increased very much on an individual application basis, but in the time since, there are now a lot of peripheral apps now that are considered a must have for many in online gaming such as OBS, discord, etc.
In a gaming sense, in your example of bloated ram usage, often this applies more to VRAM, but hopefully the truly bloated games that are worth playing can be tweaked in their settings to reduce the bloat for lesser provisioned systems. Generally one can get by with a really minimal system for years by running lower settings, sometimes by modifying ini files. A lot of the demanding settings are actually very subtle visually, and gameplay does not suffer as a result of disabling them. However, you generally can't go wrong with getting a higher VRAM card if the option exists.
Right now, because ram is relatively cheap compared to the last 4 years, I'd probably go with a 32GB system if building a new machine, just to extend my system's useful life.