I do think both the portal and NIL are making it easier for the big WBB schools to fill their roster with talent at the expense of everyone else. HS recruiting was always a crap shoot, and still largely is, but the portal is a supermarket for talent, and the word seems to get out that big money is available for sophomores-senior with the right talent. Raiding the mid majors of 'surprise' talent is happening in a big way, and raiding fellow P4 conference is also rampant. There are a number of completed transfer the first few days after the portal opens - it would take longer if there wasn't back channel information flowing.
I am not accusing schools with tampering though I suspect there is some. But they don't really need to, social media and a player's posse get the job done.