There are definitely some similarities, agreed. But each situation is different. The most glaring case was Jarvis Landry. Looking at the production, he didn't score TD's from one of the few positions where you can generate TD's, so he was clearly not at the top of the WR market. Looking at his position--slot receiver--he was among the leaders there for sure. But, that is a lower priority position than outside receivers, primarily because it tends to not offer TD's and defensive attention. Speed receivers open up play even when they never see the ball, because they stretch the space underneath for those slot receivers, TE's and RB's. They command double-teams from safeties freeing up the RB's to run against 6 or 5 man fronts and generate most of the chunk yardage running plays because after the thin front the DB's are left in space 1v1 with a RB until after he has gained about 10 yards. Slot receivers don't do that because they typically are quick but not fast (like Landry) and their routes are designed to exploit the space created by those fast outside receivers. Those slot receivers are doing it vs. 1 on 1 coverage most of the time. Simply not fair to look at catches and yards and ignore all of the non-stat things the outside receivers are doing. Slot simply isn't as high value of a position as outside receiver.
Olivier Vernon was a pass rusher and that is definitely a premium position. But, Vernon was a developmental project out of the U, and he only really had one breakout season. One year flashes are bigger gambles than they seem, and stats often show that when that one year is a contract year … the chance of being let down increases. While I advocated signing both of those guys to extensions years prior, that wasn't the front office's decision, leaving us with two bad choices--pay an incredibly bad price at market value when the player's stock is at an all time high, or let him walk. Tougher decision, but again, IMHO, we made the right decision. He wasn't worth the money. In both cases, the Dolphins decision was proved to be the correct one. In both cases, it probably would have been more effective if we had signed those guys to extensions earlier, when the money was workable.
Flash forward to today and Xavien Howard. Similar to Olivier Vernon, it is a marquee position and he is a player who only recently came into his own. If we can negotiate a reasonable extension now, I definitely think we should do it, because finding dominant CB's who produce takeaways is extremely tough. Finding ones that do it without a fierce pass rush is even harder. IMHO, no 1st round pick is going to compensate us for the loss of a top young CB1. But, this is happening in a year we are tanking and if we fail at tanking will need next year's draft picks to move up and get our franchise QB. Without that QB, I have little faith our rebuild will be successful. Also … I'm tired of watching the Dolphins suck on offense, it's not as fun. But I digress, back to X. He is still on his rookie contract, so worst case scenario he wants to be paid top dollar, we still have the option of franchising tagging him (who else would we franchise?) which essentially pays him at the level he wants and buys us another season to determine whether he is a flash in the pan or a truly great CB. If he's a flash, we resign him for less or let him walk and get a compensatory 3rd. If he's the real deal, we're back in the same situation. To me that seems like our Plan B if we can't reach a reasonable extension. I see no version of this story where we are as good or better off from a talent standpoint than we would be with Xavien Howard. His position is too important, too hard to find, and generally requires cultivating over multiple years. Trading him is not likely to net us a younger X.
But as you so correctly point out, there is such a thing as too much, and if his agent is dead-set on becoming the highest paid CB in the game, as Landry was dead-set on becoming the highest paid Slot in the game, and Vernon was dead-set on becoming one of the highest paid pass rushers in the game … then we would be making a foolish decision to back up the brinks truck for the guy. We're not a Super Bowl contending team and he is not the piece that gets us there. We're in full rebuild mode with a one year hiatus for tanking. So, if we need to trade him, even though it is a net-loss of value … it's a good time to do it, and it's not the worst decision in the world. At least the first year of being without X will not be a problem … since we're tanking anyway. But, it makes sense to keep the negotiations open, franchise tag him if we must, and then if we still can't do business, part ways then. At least, that's how I see it.