Sure, Amazon shouldn't want to kill it off, but what if they do anyway?
Remember the guy who posted a few weeks ago on HN about how 'google fired me'? It's pretty easy to make a small violation of the TOS without realizing it.
I'm just making a suggestion - don't put all of your eggs in one basket. If you depend on one company for 100% of your revenue (Google, Paypal, Amazon etc)that's a huge risk.