I don't think it's about laziness, I think it's about the amount of budget they have. Konami know it only sells to a certain crowd, but it sells to them no matter what, so why invest in it? They're not thinking "spend money to make money", especially not with fierce competition. They're thinking "spend a little, make a lot". The guys working on the new content are probably working for a couple of days a week, especially post-release.
This is why community editing tools are so important. It's morally wrong to expect your community to do all the work, I think, but... It's the only way it'll ever get done.
Give us an even SLIGHTLY complex stadium editor and every team would have their own, authentic-looking stadium by November. Not just a couple.
As for why they remove generic stadiums and good features... That one's trickier. General incompetence and/or programming issues with certain amounts of stadia caused by general incompetence which is partly due to the low level of investment in the game, I would imagine.