1500 hours in a C150, over flat terrain, under clear blue skies, potentially operating from only one airfield, would be utterly meaningless, when moving to a twin pilot passenger aircraft.
Complete garbage. Suzy C150 driver has made 1500 go/no-go decisions, 1500 preflights, 1500 run-ups (more decisions) 1500 T/O's, 1500 en-routes (more decisions). Of the 1500 landings at least 25% will be crosswinds, some flights will be RTB early because of changing weather of mechanical concern (more decisions). The C150 driver will in those 1500 hours experienced shaking knees and dry mouth at least several times because of circumstances that arose unexpectdly such as, weather, mechanical, fuel concern, lost, etc. These things matter and are lessons that will never be forgotten.. I could go on about the importance of time in the saddle and how successful aviating is a continuous chain of decision making where the wrong decision could cost you your life. SIM world is wonderful but you will never kill yourself therefore you will never make life/death decisions.