In both -19 and -20 Tavares played for some pretty good teams but still couldn't put it together. The Islanders became a playoff power house without him.
Indeed these past two years have not gone well for Tavares, and it's never a good look when a big name player leaves a team and they get significantly better without him. Happened to Bobby Orr as well.
That said, Backstrom's stats are propped up tremendously by playing with Alex Ovechkin, and it seems a lot of posters are just looking at the points here. Since Tavares entered the league, Backstrom leads the NHL in secondary assists by a pretty large margin - 291, next is 255. JT has 167. An unusual amount of Backstrom's points are powerplay secondary assists - the weakest of all points. Often times those are mundane uncontested perimeter passes back to the point (Green and later Carlson) who then pass to Ovechkin for the one-timer.
In terms of primary points since 09-10, Tavares has 652 to Backstrom's 532. JT has 364 goals to Backstrom's 222.
I don't think there is much difference between them defensively.
I don't know why people are talking so much about hype. It's irrelevant.
JT has been the better player.