Steemit.com running on the tron blockchain with the steem-tron token amd the others like busy and esteem etc run as it always has...on the steem blockchain with the original steem

That is pretty much exactly how I think it could pan out. It will be up to the other front ends to decide which blockchain to use and some clever (ambitious) devs might even try to do both - a little bit like Steem2wls but maybe a step further to show balances on both chains too.

Who knows. It sure will be interesting to see how it plays out though.