[Tenhundfeld]

Yes, I think this is an important point: They have 14 other developers to count on.

If you were the sole developer or on a super small 2-3 person team, I'd empathize with your reluctance more, though I'd still advise it's time to get out. It's not really that you owe the "company" anything; it's that you don't want to leave your teammates and friends in a terrible situation, etc. I get it.

But being a member of a fairly large team... nah man, you should feel zero, absolutely zero guilt about leaving, IMO. I would feel no negativity towards you as a teammate. If you are truly irreplaceable on a team that size, it's just another sign that this project is being mismanaged. GTFO! :)