Why are conjugation and sporulation not considered as forms of reproduction in prokaryotic cells? What are the main purposes of these processes?
By themselves these processes do not actually result in a second cell being made. ie there is no reproduction.
In conjugation two prokaryotic cells join, exchange some DNA and then separate. Two cells enter, two cells leave.
In sporulation one cell turns itself into a spore to survive harsh conditions. One cell becomes one cell.
In both cases actual reproduction can precede or follow, but this is accomplished by regular cell division.