This isn't new, Kucherov and Vasilevski as well signed 3 year bridge deals that extended the Lightnings window for years.
Long term deals can work coming off ELC's as well as long as you do not overpay for potential, look at MacKinnon for example, he signed what was a fair deal that turned out to be a steal on the back half of that contract. Ekblads contract has that same potential, where as guys like Marner and Matthews are awful because there's no potential on getting good value at their price.
Mack signed that deal cuz he didn't have numbers to gain better leverage. He was coming off a 38 and 52 point season and put up 53 his first year of it. So he was also paid for potential aswell. If he hadn't broke out and if he had stayed at a 55 point player that contract wouldn't be lookin to good as of now. Colorado got lucky that Mack is as good as he is now but if they had gave him a 3 year bridge Mack would be looking at Mcdavids dollar right now.
As for Mathews and Marner contracts, they were signed looking at their elc productions and the nhl future revenue in mind. Marner coming if 94 points and Auston coming off historical elc goal scoring.
Also gotta remember the talks then was the cap reaching 90 mil after tv deal and expansion.
No one saw covid coming, if it hadn't we would be looking at a lot more 10mil rfa signings but it is what it is. In hindsight a bridge deal would of been the best for Toronto but again who saw covid coming.
The contracts not great value compared to guys like drai and mack but it ain't awful like you're trying to say. Auston in his first year has earned every dollar and mitch lost a mil and half in value. No extra value but not awful either.
All leafs can look forward to is them playing up to their contracts and so far Auston has. In fact Mathews has earn more bang for the bucks in his first year of his new contracts then Mack did in his. Mackinnon first year was neg value, it was a disappointment and an overpay but he gain it all back and then some the last 3 seasons.
Leafs contracts has no chance of gaining extra value now due to covid but both have a good chance of earning it. Although again imo Mathews has already done that his first season of it, now its up to mitch and he is capable of it aswell. Mathews contract value will hopefully be seen in his next deal where he signs for 12ish while these bridge guys hit the 10s and 11s million per... We shall see.