Let’s say this was allowed, do you think that would help or hurt the recruiting for teams who choose to operate that way? They would have to guarantee money for 4 years to guys who may not pan out and for some recruits it may be a turn off.
Or, you do what you can to develop guys, take care of them financially, and treat them well. Sure some might leave that last year of eligibility like Parco, Teemer, and Figs but recruits take notice and it probably is a net positive in the long term. Also, sometimes it may be a good business decision to let 5th and 6th year seniors go elsewhere.
Since you are an ASU fan, my recommendation would be for your coaches to spend less time moaning about guys leaving and more time touting the accomplishments that they had while at ASU and congratulating them on getting paid for that final year. That will go a long ways in the wrestling community IMO.