The root of all of this angst now is the influx of African distance runners. It makes people uncomfortable and there are many reasons for it: some objectionable (racism) to those that search for fairness.
Nobody seems to be complaining about sprinters from the Caribbean, or middle-distance runners from CA, UK or Ireland.
IMO, the first issue with the runners that come through a recruiting service is the cost. Not only are you paying the service for the athlete to come (and pay the athlete), but you are also paying much more tuition if you are a state school, especially those where funding of 'fulls' is based on in-state tuition values. That just dominates your budget.
Doping. This has to be considered since 'kids' have been caught. I am not sure how a service that supplied student athletes caught doping would survive, but hey, winning is the only thing that matters! There is also a very obvious doping issue in Kenya, so it cannot be ignored.
Transcripts. As someone who worked in D1 and D3 college athletics at one point, this is rampant everywhere. I have personal evidence of doctored or fake transcripts from Eastern Europe and even the US (disguised as homeschooled when the SA actually went to a physical school up until about a month away from when they supposedly graduated a year early with 6 additional courses completed). To think this is not happening is foolish. Our head coach did not enroll these students, but he also did not fight their eligibility when they enrolled at nearby conference opponents (D1). Coaches hate pointing fingers at other coaches for fear of being blackballed and if it can slip past compliance and the NCAA then what can you do?
Age. Verifiable ages. Birth certificates are tough in some of these countries and subject to forgery. Not all of the time, but we know it is happening. Not everyone was born on Dec 31. ;). Yes, some of this can be solved with the 5-for-5 or other ideas expressed on here, but the NCAA dropped that for at least a year due to so many lawsuits currently out there, including the Diego Pavia ruling.
Damage to your alumni base. When you start to work with a transient population as is beginning to happen with the influx of foreign talent and the transfer portal and don't build a team, you probably won't have much down the road as far as alumni support when the school decides it wants to cut the program.
At the end of the day, how many schools win it all? One. Does your AD really care that you made NCAAs and made the top-5, 10 or 20?
I also find it funny about how some coaches have been quoted re: the situation of recruiting foreigners and the benefits but in recent talks with club coaches and parents during recruiting said the exact opposite this fall. Yes, I had a coach say this to me.
The bottom line is some coaches want to win at all costs and will do everything they can in the short term. Others will be forced to play the game to some extent to 'keep their jobs' unless some changes are made.