Voters will vote, because 1. they might get LISK and even more importantly 2. they secure the whole network with their votes.
#2 is altruism and will not be a motivation. #1 is the right answer.
Why do we exclude entire countries? Where did I say you MUST join a pool? People don't need to be completely public, a well known username is often more worth than a real identity.
Usernames are not worth more than real identities. That's why the LISK development team used their real identities for this ICO.
Real identity is more legitimate than a user name, but it is going to exclude a lot of people and undermine the robustness of the system.