I’ll disagree, In the early years of the league, certain players were so dynamic and popular, considered so important to the league, that a short career did not hold them back.
Namath was in this category too. For a few others people considered borderline, just look at what they meant to the league
I don’t remember people talking about returners as HOF. I think it was early 80’s before they made the pro-bowl. Upchurch might have been taking a WR spot. I think Steve Tasker used to take a WR spot as well. Don’t think Special Team was added to 2010
Maybe Sayers still gets in the HoF without the returns. But it’s impossible to separate his running from the returning because it is all part of his legend.
I think it’s fair to say his special teams play was clearly dynamic and helped his cause but he was not a “special teams specialist” he was great offensive player who remained a special teams player.
Tim Brown is a guy who went from great special teams player to great WR but without his special teams contributions he too might not be in the hall. I’d have to go back and look at his career.