Not cleaning your gun leaves excess debris that is being reciprocated back into the frame/the riles etc... as the gun is fired. The less the better. 2011's these days (depending on slide/rail/frame fit) can go quite awhile without cleaning and still function, that doesn't mean it's a best practice or optimal. Only cleaning when functionality is compromised could have led to OP's problem.
Yes, I'm sure owners of Bugattis/Ferraris/Lamborghini's are using 0W-20 in their engines. Certainly not a synthetic grease of any kind. That would be preposterous -_-.
Redirecting your statement to the context of this thread: any high-end 2011 manufacturer recommends grease. When I received my SVI it came greased up, along with a recommended grease product from the factory. In talking with sponsored shooters from PT and SVI, I've also found that grease is used more often than not, especially on parts/areas that see a lot of violence (slide stop pins, barrel lugs, etc..)
OP was asking for suggestions, and I gave my opinion on the subject. Ultimately my advice is worth as much as you're paying for it YMMV. There's actually been a few threads/research on this subject and the consensus always leads to: grease protects parts from wear better than oil. If you find evidence of otherwise, please send it my way, I'd be interested to read it.