Most airlines board back to front, excluding business and first of course. But it just ends up taking the same amount of time as front to back. It's not the people taking seats on an empty plane that is the problem. It's the last few that are having trouble finding overhead storage and have to hunt up and down the aisle for a place to put their bag.

Also, you can't give up business entitlement. It's built into the price and the passengers paid for it. The entire reason they buy F/J tickets are boarding priority, good seats, better food, newer IFEs, and higher luggage allowances. They also get a glass of champagne or wine, something they wouldn't be able to receive if they were the last to board.

Also a coach and F/J fare is the difference between a $1/pass and $1000/pass profit.