Even World of Warcraft which used to be seamless in terms of issues, has had increasingly more and more obvious bugs. A sad state from the "Blizzard polish" of yesteryear.
World of Warcraft has never been without issues. When it launched it was full of bugs, servers kept crashing (but they did refund a lot of gametime back then) and so on.
And every expansion was just a nightmare start, without being able to get to the new zone, servers again crashing.
You just have golden memories of a state that never happened. Game wise, WoW has gone forward a lot since DF (the disaster of SL taught them something) and is actually in a lot better state than before. Sure, it has bugs, but it's also a massive game. And they do keep fixing a lot of bugs with quite good response time these days instead of what it used to be.
Bugs and infrastructure are two different things. Yes when a game first launches it will potentially be quite buggy, but every expansion until recently has been impressively slick.
Try playing WoW with a new account. The initial mission has incredibly ugly graphics (much worse than the main game), a flat progress bar during loading (literally just a simple blue rectangle - no borders, gradients, or shadows, just something that a basic box(x, y, x1, y1) function would draw), and a yellow rectangle instead of a rope connecting your hero to a flying vehicle. It’s not a 3D bar, just a 2D yellow rectangle that looks like a censorship block on the screen, and you’re supposed to imagine it’s a rope hanging from a helicopter-like vehicle.
I understand it’s an old game, but these parts seem like pure laziness. I’m sure this laziness costs them a lot of players who leave the initial mission in disgust and never get to see the beautiful parts of WoW.