Plenty of walk ons become valuable role players at top programs.
Define plenty.
My name is not Google. Wanna look it up? Have at it.
So if you make an absurd statement that "plenty" - a word meaning among other things "a large quantity" - of walkons have made an impact at "top programs" I have to use google to discover whether your absurd statement is not false, otherwise it's true. That's quite stupid, even for someone who routinely leaves a trail of stupid rogue waves in his wake.
For non stupids, the burden of proof for an assertion is on the person making the assertion. The burden is not on the person who disbelieves the assertion to prove the absurd statement is false. Prove your statement true, else it is false.
I can think of one walk on who's made a significant impact at St John's: Andre Stanley. SJU is allegedly a top program. Anecdotal evidence suggests you're talking out your ass. Therefore you are.