Since the founder came back, his priorities are not the same ones you signed on for, and the company seems to have drifted to another direction.
In this case it isnt about the blame game which is very common these days, but to accomplish what you can for them while you are there. If you have a boss with any semblance of a spine, let him or her know that you will take his directives, but not to get tangled in thier political crap.
In the meantime start putting the feelers out at some of the other stops you made on the way. If I recall, the old job was worried about losing you, its very rare that you can go back, but it is not unheard of, I left my company 6 years ago, and after 4 years away they took me back at the new salary. That was lucky, but not unheard of. Check to see where the guy that hired you went, if he was happy with you, he may have something in the works at his new place.
Bottom line, stay focused and keep your eyes on the exit.