Imagine if your playstyle was entirely based around exploring the underground and then Mojang comes along and removes more than half of the content.
Yes, that actually happened in 1.7; cave systems became 2.8 times smaller (as well as 2.8 times less size variation, and more when you consider overlap between cave systems; they were made twice as common but there are less caves overall and this also reduces variation; the larger the size range is and the rarer they are the more varied they get) and mineshafts and dungeons both became 2.5 times rarer. I'm not the only one who was put off by those changes, as this remark from a PM shows:
And that is exactly how I feel, to the point where I have never updated past 1.6.4 and never will (not likely or may but will), plus I have more than 121 days of my life invested in a world which I do not want to be disrupted by world generation changes. Use mods to revert them? Heh, why not just use the same version instead? Mojang actually adds underground content as well as customization in 1.14 or whatever? I have already done that myself with mods, and, of course, this is only possible on the Java edition so I'll never play anything else even if I did update:
i'm also one of these guys who just didn't update
i've played 1.9+ but never seriously and 1.12 only once to see the new blocks/etc.
tbh in my case is because of mods sure 1.10+ has plenty of mods but not those that i like or these are also aviable for 1.7.10 however this isn't about this topic
i feel like new textures are some fine and some look weird but at the end of the day you can use a resource pack and some people like me already use one anyways, I use faithful because it makes the textures to actually look cleaner and not just blurry but i think if MC use default 32x32 it would be worse than blurry 16x6