If I have ADS-B Out, why do I need to do a "Transponder Check?"

Can't the FAA take the GPS altitude, the Pressure Altitude, the local Baro Pressure and run it backward to see if my reported Altitude is within limits?

I suspect so...and like we can go online to check our ADS-B performance, why not include this in that report?

Taking it one step further, rather than do the Check once every two years, why can't the FAA let me know if my systems is approaching limits before it goes out of limits?

Maybe this won't work as you go to the FLight Levels and RVSM regime given the tolerances needed, but what if us airbreathers in the lower Angels (cherubs?) got the cost avoidance of avoiding a Xpndr Check every two years?

Please toss you stones now.

Ted