I am surprised there has been no mention of Segwit2X, this has a planned release for July 21st, and so if this gets acceptance, this will be the defacto bitcoin (imo this is the best compromise, larger blocks and segwit activation). With my understanding, if this is successful before August 1st then 148 is moot, as it is already activated within Segwit2X.
Maybe someone with a better understanding can explain this better?...
I think if you give the maximum benefit of the doubt you can possibly give the miners, they are behaving the way they are behaving because if Segwit alone is all that's implemented, they believe, rightly or wrongly, that the future for them will be collecting fewer main chain fees because of Lightning network, and only dust-like fees from actual Lightning network transactions.
Combine this with ever diminishing block rewards, it's possible they see their financial future as dimmer and dimmer in bitcoin. So really they need to see something positive from their future fee collection standpoint, and a bump to 2Mb blocks is something they can point to as a "life line" for their future.
That's the absolute most benefit of the doubt scenario I can come up with, and if it's close to reality (doubt it's the entire story) then your scenario may come to pass. It's just that this hard fork to 2 MB is going to be so difficult and so contentious....could get nasty.