a) the technical challenges at these large tech companies are probably way more interesting
b) compensation is very likely better
c) you are working with many many more peers who are super talented
Not really, if I come up with a novel algorithm or a different architecture to do a task better at Google then they will give me the chance to implement it even if it takes months or years. Small companies doesn't care about your ideas, they just want a cog that can give them a basic website because that is all they need, novel things doesn't help them.
If you mean "novel product ideas" then sure, but we aren't product managers we are programmers so our ideas would mostly be related to architecture or algorithms.
This is a very strange point-of-view.
I've worked in "small" (~100 employees or fewer) business my entire career, and not once was it strictly CRUD stuff in C#.
The freedom is debatable, I guess, since I have no experience at larger companies, but I certainly never found that my freedom is confined. Most often there is opportunity to contribute anywhere and everywhere, and management is happy to have the help.