I don't think that's true at all. Startups are all about reinventing the same wheels every time so you learn how to quickly bang out the same garbage iOS app skeleton for the 2nd dozen time but it's not like startups have cornered the market on new information. Plenty of big companies do really interesting things that you can learn a lot in
As far as the learning part, I didn't mean to restrict "learning" to only mean coding/programming/developing. At a smaller company, if there's something you want to do, you often have more freedom to take it on. There's very little "not my job" allowed or "not your job" enforced.
I realize there are several counter-examples of sociopathic micro-managing, ultra-secretive founders out there. Avoid those people whether at a big company or a small company.
At any rate, if you prefer larger companies, I think it's awesome that you know that. When I interview candidates, I always try to help them figure out their preference. It's not always easy for that person to know. Sometimes their desire for "a" job or a "new" job makes it hard for them to figure out if they want "this" job.
In any case, sorry for making a blanket statement about lack of learning at larger companies. I unintentionally commented on all large companies based only on my own experiences with large companies.