Except in a few special circumstances before the airplane stalls it has to pass through slow flight first. Personally I think there is more value in practicing maneuvering the aircraft in slow flight then there is to just going out and doing stalls.
For new PPL's I suggest that they start with a power on stall and recovery and then work at a concentrated 10 minutes worth of slow flight. And I mean true slow flight, that is flying with the stall warn horn first sounding intermittently and then even slower with the horn sounding continuously. This should involve turns and descents in slow flight. (Note 1: the initial stall practice is to make sure you have reviewed the stall recovery so that if you c*ck up the slow flight and actually stall you will make an uneventful recovery and Note 2: make sure you monitor the engine temps to avoid overheating)
I see many students get scared when they see 60 kts IAS in a C 172 or Pa 28. This speed is still way above stall speed and there is lots of margin left. The best way to not get into an inadvertent stall is to recognize the fact the airplane is getting slow just by how it feels and how it is performing. Being comfortable flying it slowly also makes operating into and out of short fields safer.
As for engine failures, well as I have pontificated on before 80 % of all engine failures are the direct result of the actions or inactions of the pilot. Even if the engine fails power can often be restored if a "cause check" is promptly performed.
As a fairly young instructor the "AH HA" moment for me involved a forced landing of a C 172 by a new PPL in very inhospitable terrain. The pilot did a great job of getting on the ground without killing anybody after the engine suddenly stopped, but when the wreckage was retrieved there was 10 gals of fuel in the left tank zero gals in the right tank and the fuel selector was selected to the right tank.
If his instructor had put the same effort into teaching this pilot the importance of a quick and effective cause check as he did into flying the forced approach, he would have been able to restore power and fly home......