I think one of the biggest changes in the community in the past few years has been this: public games and organized play are both normal - while they've been around since the 70's, they used to be a niche and a small segment of the hobby. Now it's a significant chunk of the aggregate play experience.
It used to be almost everyone only ever played home games. Now online and organized play are common, and so rules, houserules, and expected behaviors are adjusting to these facts. For a forum, this means you can't always assume people play in home games - which is why "leave and find a new group" is such a common suggestion for social problems at the table. It's also way a lot of build advice tries to stick to PHB+1 when possible; there's a good chance a reader will have to work within that restriction.
(The other big change is streaming games, but that's a different thread. (My short answer: streaming means new players have an idea what a game of DnD actually looks like in practice, and some expectation going in. Back in the 90's, IME, they generally had no idea what to expect or whet to do.)