Jobs was able to nail the coffin shut because of market share, but he certainly wasn't the first to push for removing flash - that belongs to the open-source community. I remember fiddling with debian, trying to get flash installed, and getting the answer "flash is bad for a number of reasons" and given the idea to try to use non-flash sites. When Jobs made the step in 2010, it was not trivial, but he was joining an existing movement.