1. I can throw out the closest comparable (which it isn't) if the criteria doesn't match (which it doesn't). There's no sense in shoehorning bad comparisons in just for the sake of having one. Matthews' contract, for now, is a unicorn.
2. The Ehlers contract was signed under different circumstances than Nylander's. I'll put it to you this way: if Ehlers had waited until after Year 3 of his ELC, and had put up a second-straight 60-point season, do you think he still would have signed for $6m per? He signed with less track record to his name at a time when the cap bump from Vegas was unknown. His value is deflated due to his impatience.
Pastrnak had extremely similar ELC stats to Nylander with a better platform year, and his contract adjusted for 2018-19 was $7.07M, so Nylander's AAV from Years 2-6 will come in underneath that adjustment. The most you could reasonably argue Nylander is overpaid by is maybe $200-$250k per year, based on his comparables.
3. Players shouldn't be paid based on team trophies like Stanley Cups. Toews, for example, signed a legacy-based contract that is going to negatively impact Chicago's plans for years, getting continuously worse. Kopitar's deal didn't look too great this year, either. Players should be paid based on production, and Matthews' production at such a young age is elite. Fun fact: as the cap continues to go up, so will the prevalence of $10M+ contracts, so we need to wrap our heads around a whole bunch of non-top-5 players making 8 figures.
4. So if you'd be fine with/wouldn't mind Matthews making $11.634M next year on an 8-year contract, why aren't you fine with Matthews making $11.634M next year on a 5-year contract? The impact on next year's cap, which you seem to have issues with, is the same. The truth is that an 8-year contract was never going to be at that level, though, with the cap continuing to climb and dragging annual salaries up. Very soon we will see worse players making more than McDavid.
So far we've established that you want all of our players to be on bargain bin deals, think Tavares should be getting less than Kopitar's cap hit %, think Nylander is overpaid by ~$1M because of Ehlers' short-sighted decision, and Matthews is overpaid by ~$2M by comparing him to a Stamkos deal signed under a different CBA and different RFA climate 8 years ago.
The overarching issue that we're not talking about here is this: paying your high-end talent handsomely isn't what kills you: it's overpaying your low-end talent. The collective $13.35M we're going to be paying Marleau/Zaitsev/Brown next year is what's going to prevent us from keeping Gardiner, and is what puts us in a bind with Kapanen/Johnsson. Our high-end talent shouldn't have to take less because we've overpaid players at the bottom of our roster.
Do you not realize that I am agreeing with you that Matthews' contract isn't necessarily deserving? And that I'm stating it's because of his injuries more than his production itself, which has been impacted from them. As I've explained.
