Two words: Subpoena power.
The biggest hindrance to an NCAA investigation is they can't compel someone to talk. Ask Danny Sheridan, Terrell Prior, Cam Newton, or Bruce Pearl. True, there are tough penalties for lying, but if you get your house locked down, they can't come in.
That is unless they can get the information some other way. Such as through a bankruptcy proceeding. Which you usually have when a Ponzi scheme falls in. All 72 Miami Hurricanes that allegedly received benefits are going to be subpoened. Some of them allegedly got plenty of benefits and have plenty of money with which to pay it back.
It'd be easier sneaking the USS Ronald Reagan into Moscow than keeping all 72 quiet, especially considering they are all on the hook for perjury if they lie and contempt if they ignore the subpoena. It is only a matter of time before the NCAA has more than Yahoo! and a convicted felon's word to go on.