when written "Just give one season or two notice so we can prepare" you're basically asking for 3 to 6 months wait. That's bunch of time
This is a slow game. Training requires a long term plan. Planning years ahead. Your own words should lead you to see that if you've set plans in motion that require years, then change is not necessarily going to be good for you. Even 3 months isnt going to help if you're halfway through a 3 year plan. But its better than nothing.
Also, we're used to getting advance notice. It always used to be the norm. Why has that changed?
Previous game engine changes have been tested in scrimmages and private leagues. Why was this not done this time?