How hard is it to toss a board under the trailer wheels and pull onto the board?
Answer, pretty easy.
How hard to toss boards under two or more wheels of a motor home?
Answer, not as easy as a trailer.
Not saying there isn't any TTs made with built in "levelers", there most likely is some but in reality it would be a very expensive item which has a tendency to fail or break down at the worst possible moment when you need it to work.
They do make levels with markings in 1 inch increments that takes most of the guess work out of leveling a trailer.
When you get to your site, check the side to side level before unhitching, place your wood or plastic leveling blocks in front or behind the trailer wheels then pull on to the blocks. Now you have side to side done.
Place your wheel chocks then unhitch.
With trailer unhitched lift or lower tongue until you achieve front to back level.
Now run stabilizers down.
Done.
Motor homes leveling can get pretty complex and built in levelers make the job of leveling a lot easier.
Travel trailers, not as difficult to level since you are dealing with wheels in same close space making it a much simpler task without automation.