It is not impossible, but you need some factors to line up in your favor.
The Cliffs Note version: if the recruit's preferences (playing time, location, offense/defense, etc) line up better for the B- team than the A+ team AND the B- team goes heavy after the player, they can get high enough probability odds to possibly grab the player.
For example, if you have a recruit from Cincinnati who wants to play close to home, wants motion/zone and playing time, a B- Xavier motion/zone squad can compete with the A+ Georgia Tech fastbreak/press team to land the recruit. But if A+ Ohio State also runs motion/zone and offers start+minutes, Xavier is in trouble.
I think the biggest difference to adjust to is that in 2.0, the team that put in the most effort always won; given the prestige differences, most B- teams couldn't invest enough resources to beat the A+ team 51-49 for a recruit. In 3.0, putting in the most effort gives you the best odds of landing the recruit, but does not guarantee you the recruit. Hence, HD players complain about "bad beats" where they were 70% to land a recruit and lost him to the 30% team.