Since Ashton Vale was announced, and with the impact of financial fair play rules I've always felt that, as far as our stadium is concerned, doing nothing would never be an option.
Ashton Vale would have given the best chance of putting in place all the facilities that would enable the club to maximise income both on match day and also on non-match days - hotels, conference facilities etc.
I don't think that AV is necessarily dead in the water, but suspect that SL realises that to get it will take a long game, so in the meantime the only alternative is to make the most of AG through redevelopment. Ok it might not give us a hotel and conference facilities, but we can get better spectator facilities and some corporate boxes in place and while we are in league 1 will we really miss a 30,000 capacity?
At the time AV was announced we could conceivably have been a season from the prem. Realistically, and with the new football philosophy, player recruitment and bringing through young players we are at least 5-7 years from a shot at the prem - baring something quite remarkable so will we need the ability to increase the capacity of AG if, during that time other stadium options materialise - either AV resurfacing or your idea of SL having a trick up his sleeve.