You're the one misunderstanding.
A big company don't take any risk to file a patent, it's a few thousand of dollars and a few lawyer hours, and that's chump change for them. And that's a great sum for the small guy.
That's why you see companies like IBM, Samsung, Microsft and Apple patenting the hell out of everything. It's actually a great defense move (so, yeah, it's the inverse of risk) and sometimes take no research (just lawyers and money).
There are some patents that USPTO keeps rejecting from Apple, and Apple just changes the wording and try again (no small guy can afford that) until they finally get the patent. Such a wonderfully new researched and risky idea shouldn't take more than one try on the USPTO, don't you think?
Obviously I'm not referring to the process of handing in a patent application when I talk about risk. I'm referring to the process of inventing the invention that's patented, which presumably takes a lot of time and money in R&D.
Patents are not rewards for invention. They are compensation for willingly disclosing what would otherwise remain trade secrets. That's why the application has to describe the invention in enough detail for others to implement it (not merely recognize it) and why it must have been kept secret until the examiner's decision.
The fact that simple ideas can be truly novel inventions, worthy of protection, is the main problem with our patent system at this point. Not everything that is simple is an invention - and that means the only way you can tell if something is worthy of protection is to have some deep domain knowledge. The one thing our patent examiners do not have.