At the risk of stating the obvious- it doesn't matter how innovative a company is as a whole, it matters how innovative what you're doing is. SpaceX does some really cool stuff, say, but you're not a rocket scientist- managing their financial software wouldn't be cooler than it would be for anyone else's. Conversely, Snapchat is just a goofy app for teenagers, but whoever writes the facial tracking system they use in their photo filters is doing some neat science. I don't know what the insides of Google are like, but I would bet that if there's anywhere a mid-career programmer can gain some interesting new skills on the job, it's probably somewhere in there- and that will get you a more interesting position, whether you stay or go elsewhere in the longer run.