So why isn't the SLA technique tought in the PPL syllabus?
It is in some places.
There is no specified forced landing procedure for the PPL or the CPL. The requirements in simple terms are to maintain control, ensure safety and make it to a suitable landing area.
The great thing about the SLA is that the basic methods involved can be taught and learned on the ground using a suitable open space and teaching aid.
Looks funny with students walking round arms outstretched dipping down as the walk! One even tried to be smart and make engine noises until I pointed out that this was an engine out procedure.
Regards,
DFC