It's been well published that Iowa walked away from Bollers. (Read: "T.J Bollers Unsure Where He Stands WIth Iowa Football Program" by Tyler Devine).
Bollers stated that he was "confused by the lack of communication and that he is waiting to see if Iowa reestablishes a steady line of communication."
He also is quoted stating the following: "there are other places that are putting in effort to come and see me and make it to my basketball games instead of saying they would and never coming."
The reasons why Iowa walked away are unclear and only speculative but it is a certainty that Iowa moved on before TJ did.
Second to perhaps only offensive line, defensive end is more than in good shape for the next few years. In 2020, they got Deontae Craig, who had offers from OSU, ND and Mich.
They have a current top 100 player in Graves committed to 2022. Yahya Black was rated as a 90 grade, 4 star by 247 and Bowie is a high three star.
Bollers would have been a nice luxury to have, he's certainly not a can't miss prospect given the incoming position depth. He's also probably correct that he's a better fit for a 3-4 OLB.