Sorry chaps the notion that old jet VSTOL contenders failed just because they were short of thrust is too simple. They all had problems with one or other of these things (sometimes both).
1 There was no provision for keeping the hot efflux out of the intakes.
2 The lift systems left little room for anything else.
Putting more thrust in to such designs would not have helped and with some aircraft (D031 for one example) would have made matters worse.