I remember Ryan's last year here, he was pretty inconsistent, and there were lots of fans squawking for him to be replaced. And he was. And now those same fans are screaming that cutting him was one of Thompson's biggest mistakes. You're never guaranteed that bringing in someone new will make things better. It's not uncommon for things to get worse.
If Crosby's problems were having a significant impact on this team's success, I'd say, sure, replace him. But I don't think it's worth trying to replace the kicker who was 6th in the league in completed field goals and 4th in the league in completed PATs. He scored 129 points for us last year. You can count on one hand the number of kickers in the league who scored more points than Mason Crosby.
So we bring in a kicker with a higher completion percentage but an overall lower scoring contribution. How does that benefit the team?