The reason is that all good .com domains are taken or squatted. Also, ships don't use flags of convenience for their colors but for laws that are advantageous to them.
-1 for defeating a strawman argument in the second sentence:
Also, ships don't use flags of convenience for their colors but for laws that are advantageous to them.
The parent posting didn't question that. On the contrary, the fact that ships chose their flag by law instead of color - that was exactly the parent posting's point.
Lack of domain names isn't as much of a problem as it was 5-10 years ago, due to:
1) Mobile apps
2) Search (especially search-in-address-bar)
3) The fundamentally large namespace
I'd still rather have a domain like "tryfoobar.com" early on rather than foobar.ix or even worse, foob.ar or foubar.com. Provided foobar.com isn't a competitor, porn site, etc., and that I can make efforts to buy foobar.com/net/org/co.uk/jp/etc. with time if successful.
The only strong argument for (ab)using a ccTLD, IMO is URL shorteners.
