Bip 148 will most likely not go off if its main goal( Segwit ) is activated before the deadline, but regardless, Segwit will 100% happen whether it is through 141, 148, 149, 91, or Segwit2x. What people are concerned about at this point, is what will happen after. Frankly I think the best solution for the majority that believe in bitcoin is to activate BIP 141, but other prefer to take a more aggressive approach, and that's where 148 comes in.