There were lots of different vendor specific graphics APIs back then, so that was a lot more complex even if the games were much simpler.
I do think it's partly that the games are much larger and more complex now, but a lack of quality control and care still plays a very significant part. Just look at stinkers like Jedi Survivor.
You say that and yet the thread was full of people claiming "Well I've not had any of those problems", must be magic.