That statement is very hard to quantify even within the same industry.

Apple makes and will continue to make great products for a specific subset of uses because they are willing to make big investments and are very opinionated about optimal user experience. The end result of that is the often great experience of their ecosystem today.

They obviously also employ tactics to lock out competition too (see the purchase of AuthenTec, Dark Sky and a few other small purchases of best in class companies explicitly demanding that they don't work with anyone else).

Innovation in reality is "improving things" and many many companies suck at defining what an improvement is and who the improvement is for. Too many focus on improving revenue numbers and that's it instead of improving user experience, reliability, security, privacy, etc. All things Apple cares deeply about*

* Again, Apple's decisions are only an improvement to a subset of users but that's really all that matters to them. Happier users means more use of Apple products which is a win.

Because it is hard it is not impossible.

That still doesn't make much sense if innovation is supposedly easier for small companies.