I think the biggest difference between Tampa and the NYI besides talent and depth is that Tampa clearly plays like they want it more. NYI have played complacent at times they should've been more deliberate with the puck and on their toes (i.e. game 2) and Tampa has the experience of failure in the past and they've learned what it takes to win. Never let up, put in full effort for the entire game. They're doing that in a way they've never done before, coupled with their talent, depth, and system and it's easy to see they've finally become the team they were supposed to be for the past few seasons.
Sure, the series isn't officially over yet, but they're clearly the better team and should wrap this series up in the next game. No shame in that, the Islanders made it further than 27 other teams and were never expected to make it to the conference finals. They can build on this moving forward and players like Barzal can learn from it.
I agree with a lot of what you said, but the whole "they want it more" is a really silly thing everyone brings up way too often. Every player is a pro, and it's the freaking Cup. There's blood, sweat, injuries, like 50 times a game guys try to block shots with their bodies. If a team looks like they don't want it, it's because the other team is imposing their will. Washington looked like they didn't want to play because we smothered them during that series and crushed their will to live. They wanted it, we just broke them.
Tampa is just better. Everyone with eyes know it, and I'm sure there are blind people who can hear that Tampa is better.
That being said. the narrative of the Islanders being some scrappy little team that doesn't belong in the ECF is also a trash take. "Not being as good as Tampa" is a litmus test that no one else in this league can meet. TB won the President's trophy easily last year, and then spent this regular season adding grit, size, and a better defensive structure to avoid a repeat of the CBJ series. Like, they straight up didn't care if they lost regular season games along the way as they improved their defensive play. For them it was about getting better and better with their structure so they'd be ready for the playoffs, not winning the President's Trophy; because they knew they were good enough to make the playoffs as a top 4 seed even while focusing on "improving our D" over "winning regular season games."
So Tampa is really, really, really good. But the stats do not back up some kind of "Tampa domination."
CF% 51.77 to 48.23
FF% 52.55 to 47.45
xGF% 52.94 to 47.06
HDCF% 52.21 to 47.79
53 to 47 isn't domination, it's a slight edge. Which means the Islanders are actually GOOD, TOO. Just not as good as the best team in the league.
There's one category here that Tampa has been dominating:
HDGF% 68.42 to 31.58
Basically, Tampa finishes their chances at a way better clip than the Islanders (Although a lot of that stems from a staggering 87.50% in Game 1) and this is a "well duh" because they (a) they've outscored the Islanders by a lot in the series, and (b) they're more talented and basically what we call "talent" is really just isolating players "finishing ability."
It's also really interesting to me that Tampa has a popular pick for "Best Goalie in the League" and everyone is attributing the difference in finishing to a lack of offensive talent on NYI and not the difference in goaltending between the NYI combo that excels in a system, and TB's elite all-world netminder.