What will happen after all bitcoin is mined? And what is the estimate of when this will happen?
probably nothing... Miners will probably continue to mine blocks if the miner fee's that were included in the transactions were sufficient for him/her.
If the fees were insufficient, some miners will drop out, the diff will decrease, the remaining miners will mine more blocks, thus collect more fees... everybody happy
What will probably happen tough is more and more private keys getting lost over time, so more and more bitcoin will go out of circulation. Combine this with better adoption (more people using bitcoin), so the price will probably rise (long term)