History and practical technological application has already proven that more ram is ALWAYS BETTER in both short term & long term computing usage considerations.
If anything, history has proven that cards usually get obsolete in other ways before VRAM capacity.
Because it's a midrange card which doesn't need more.
That's an opinion. Not everyone shares it.
Actually not.
For the game resolutions and performance intended for this card, 6 GB should be plenty.
Exceptions would be people who have other use cases which needs more VRAM, like content creation or development, but those are edge cases.
Because buyers are clueless and think they need more VRAM than they actually do.
Another opinion, one that does not take into consideration all use-case-scenario's or future gaming developments.
Nope. This has been the case since at least the Radeon 200 series, where people keeps arguing that certain cards are more "future proof" due to more VRAM.
The best prediction for future gaming would be current games. Usage of more VRAM per frame would require more bandwidth and more computational performance, and it's very unlikely that future games would somehow manage to use significantly more VRAM in a single frame and somehow maintain the frame rate without
also requiring more computational performance and bandwidth. The only way to do this would be to utilize some new rendering algorithm which somehow consumes more VRAM capacity more than anything else (and not require new hardware etc.). This highly unlikelihood is why such predictions about VRAM has failed over and over again for the last 10 years. Games will continue to get more demanding, but there is a proportional relation between computational workload, memory bandwidth and memory capacity (especially the last two), which seems to remain fairly consistent over time, even as games increase detail levels.