This is less heartless than you're making it out to be. We are literally trying to build an equitable and comfortable afterlife that most people can be happy in
Perhaps the tax code can be revised to encourage consensual, uh, emigration once the small matter of constructing a new heaven has been resolved?
How about the first reincarnation is tax free, and the reincarnated is free to select a longer lived species for their new lifetime, to compensate for any previous capricious circumstances of birth in their first lifetime?