Let’s put it another way. Do you know off the top of your head if Easton Cowan or Matthew Knies has a schedule B bonus? Or how about recent Top 5 picks in the league like Leo Carlsson or Adam Fantilli or Shane Wright?
My point is if you weren’t invested in the notion that Player X got screwed, you wouldn’t care about this level of detail. And bringing it to light does not win hearts and minds. Marner’s going to make $125 million in his career. Losing out on $2 million in 2019 isn’t the most relatable gripe.
It seems like you're missing the point and projecting your own bias in the situation.
I've said that performance bonuses as far as schedule A&B were known on a fundamental level by many, it's also well reported how Lou handled these situations not just with Marner but with Adam Larsson in NJ then his (debatable forced change of heart) with Matthews. When Lou is a guy who stands on his morale high ground, it's tough to immediately backtrack on your position a year later. That would be understandably frustrating as the player who took less.
You could argue that shouldn't have influenced his RFA negotiations (I would say it shouldn't have), but it doesn't change the fact people knew about the bonuses prior and that it was news at the time when other similar level players were getting both bonus categories.
It seems reasonable to say that the Marner contracts have been mishandled by all parties. Lou set a precedence he couldn't uphold for other picks, Marner used it as leverage and asked for a contract that has added additional pressure he's struggled to handle. Dubas simply signed on for too much, he had too much faith in Marners abilities.
Typically the big bonuses (schedule B) are for higher picks btw, so you won't see many on later first and beyond round picks. I expect Cowen doesn't have one, nor does Knies (we'd have heard about Knies given our cap situation btw). Carlsson likely does as do most recent top end picks. There was a weird, short term downturn in bonus contracts for top picks around the cap freeze periods after COVID, I believe they've bounced back now to more common 2+ million range for top 5 guys. We also used to see it on highly sought after undrafted NCAA players like Bozak who qualified for entry level deals
I'm getting further away from the info as we pick less and less (and I get older with less time on my hands), so check the work if you think it's wrong.