Why do we need 3rd party users (miners) to confirm transactions and update the blockchain for us when anyone who has a valid copy of the blockchain can do it for themselves? By getting rid of 3rd party confirmations, transactions would be nearly instant and there would be no fees.
New coins can instead be generated as a % bonus to payees by an algorithm in the transaction process. Users could then 'mine' new coins by simply moving them between accounts and this appears exploitative at first but is necessary to compensate for deflation and create demand. Perhaps there are mechanisms that can minimize the consequences of abuse and keep it fair.
How would you pick a fork? Why not mine every fork then?
The same way we do now- by consensus. You have to accept the blocks that are reported by the largest number of nodes. The greater the number of honest nodes there are on the network, the more difficult it is to pull off a 51% attack but, without the 3rd-party confirmation scheme (mining), the risk is isolated to you alone rather than the whole network and only while you are syncing. And it doesn't waste energy.