They've let a lot of receivers go over the seasons. But we don't tend to remember those guys because they didn't amount to anything outside of Green Bay.
For instance, Jarrett Boykin was used pretty heavily one season due to injury, but was let go after 2014 and never recorded another statistic.
They had Chris Harper on the roster for a couple of seasons, and then let him go. He never did anything of note.
Jeff Janis was an untapped HOF talent according to a lot of Packer fans, and after he was allowed to leave he never made another NFL roster.
They cut Jared Abbrederis. He caught three balls for the Lions and hasn't been on a roster since 2017.
They traded Trevor Davis and the Raiders cut him before the season was over.
They cut Max McCaffrey, who then kicked around on the SF practice squad, got drafted by the XFL, and failed to make the XFL roster.
If the truth is that Rodgers holds his receivers back, then someone who gets out of Green Bay should go on to do something. But that hasn't really been the case.
Winding the clock back a little further, there were a couple of other guys whose release disappointed some fans.
Jeremy Ross went to Detroit in 2013 and returned a punt and a KO for TDs in one game against Philly in the snow and mud in his first season there. He was evidently a mudder, an OK return guy otherwise, who kicked around for few years but did little as a receiver.
Charles Johnson, who looked like he was coming on for Minnesota in mid-2014, faded pretty quickly, and was out of the league after 3 seasons. He was an AAF star, signed on with Philly last season, made the 53 man roster, but was promptly put on IR.
Jumping forward, Ty Montgomery became a running back, return man and defier of coaching instructions. He has not done much since his departure.
DeAngelo Yancy has yet to make a 53 man roster. He was signed to play in the XFL last year and ended up going to IR before taking a snap.
After being cut, J'mon Moore finally found a job on Cleveland's practice squad in late November and he's on a futures contract for their camp. Whether he gets his head straight and amounts to something remains to be seen.
The second round picks going back to 2006 all turned out pretty well: Jennings, Nelson, Cobb, Adams. Throw in James Jones in the 3rd. round. You have to go back to Terrence Murphy in 2005 to find a Day 2 pick who did not work out, and that was a guy from the Favre era who retired after 3 games when it was discovered he had spinal stenosis while being treated for a concussion.
Generally speaking, you get what you pay for. You can always point to this guy or that guy on one team or another that amounted to something coming out of the low rounds or UDFA ranks, but when you look at the vast numbers who don't one concludes it is a long shot. Moore aside, a 4th. rounder, that's where the failed receiving "talent" has come from.