I’m no fan of Rubio but the man can sell snow to Eskimos. I doubt Trump would pick him with his gang of 8 baggage. Goes against everything Trump is campaigning about. I expect Rubio is the next Governor of Florida, unfortunately.
The ideal strategy with VP picks is not to find a soulmate or fellow traveler. Quite the opposite, actually. The right man (or woman, I guess) can find you votes that may or may not have been there all along.
Thus, Reagan picked Bush. Bush picked Cheney. Dole picked Kemp. McCain picked Palin. etc.
You may despise Rubio, but you’ll be pulling the lever for Trump. Others who are not sure about Trump may be comforted by the addition to a guy like Rubio on the ticket.