Food for thought from 247 sports.
The Transfer Portal has 112 Wide Receivers committed to another school already. (about the top 25 guys are lateral or up to power 5 after that mostly down a step or 2)
There are 136 Wide Receivers still in the portal - Not counting FCS guys (which 247 doesn't generally track anymore) (They will track an FBS transfer to FCS or vise versa)
Randomly looking at schools. Utah State is listed as a destination for 3 Jackson State and Louisiana Monroe for 4. All of those schools have starters on the roster, recruits coming in, and now the transfers. Is the grass greener? Out of those 11 guys you have to figure at least 5 don't improve their playing time?? Now thinking of FCS guys transferring up..... lots of guys who have already played some or a lot, know what college football is, can assimilate to a new team, have some talent so the FBS coach picks them up - but do they play? or do they provide depth. Is being the number 3 guy at UND worse than being the #3 or #4 guy at San Diego State (insert school here)? I may argue that a back up LB, Corner, S, etc could get more playing time at UND than on a new team.