The kind of scenario you suggest is very much like a Command Assessment sim ride and those are being done all the time - I remember one candidate, (who had been a captain before), never even got off the ground, had he tried to do so he would have surely failed! Just about everything that could go wrong did and as his flying ability was not in doubt he got a whole shed load of other problems and as he reached the holding point the APU failed, in this scenario it was essential equipment, (he was dispatching under the MEL), and he rightly returned to the gate, passed!
The scenario which includes late pax boarding, a tight slot, change of runway is common and is only a test of how one handles it, rest assured if you miss your slot you are not going to be allowed to sit there in the sim for two hours waiting for a new one! The test is to see if you accept that you have missed it and ask for a new one at an appropriate time rather than rush, rush and taxy at 30kts etc. Again, the change of runway, do you tell ATC you need to re programme the FMC and re-brief and require a slot extension or give your F/O a hard time and bully him/her into rushing an unchecked revision etc? It is all a matter of getting the priorities right, you are, after all, a long time dead!
It is quite possible to do a complete Assessment or just a routine LOFT exercise without any technical failures, a favourite is the 'bomb on board' that requires an immediate diversion with half the country 'socked out' in fog! Did you select a bolt hole at briefing that was showing suitable landing weather? did you load enough fuel?
My most recent experiences in the sim have not been ones where the pressure was piled on prior to take off with a major technical failure immediately after take off, during six monthly base checks, only an engine start problem perhaps.
As mentioned above, the scenario that you suggest, Groundbased, is usually reserved for Command Assessment and LOFT exercises though different companies will vary.