Meier is just really really talented. He has 5 goals and 1 assist in 9 games since Kane was acquired. It makes sense - Meier got pushed down the lineup, where he is able to feast on easier competition. He was taking on top competition in his first full season.
Say what you want about Couture, but he was never the guy facing top comp at ES in his first full season. He was always with Heatley and Clowe and getting easier matchups. Meier lines up with Thornton and Pavelski, faces top competition, and has both the Joes looking better than they have since the WCF against the Blues. Meier lines up with Pavelski and Donskoi, faces top competition, and has Pavelski looking even better than he did before and has Pavelski looking like a legit NHL center again.
Having Meier, Kane, and Couture/Hertl down the left wings might be the thing that keeps this team competitive for a few seasons. That's not a strength that carries an otherwise mediocre team to a Stanley Cup, the way that having Malkin/Crosby/Kessel is for Pittsburgh, but it's still an amazing strength for a team.
Kane is 8th in the NHL in 5v5 ixGF, Meier 14th, and Hertl 17th. In 5v5 iHDCF, Meier is 3rd in the NHL, Kane 6th, and Hertl 22nd. These guys all have 20 goals this year and going forward I think you can expect at least 75 per season from them. They're also all beast possession players; Meier and Hertl are both above 54% xGF, Kane is 17th in the entire NHL in team relative xGF% (His HDCF% as a Shark is over 69%). I think that having Kane on the team really is an x-factor that adds more to the roster than we might realize.
Remember a while back when the Sharks were looking pretty good, and you said there might be some merit in the comparison of Carter to the Kings at the 2012 TDL and a Pacioretty/Kane/Hoffman type player to the Sharks at the 2018 TDL? That's kind of what is happening. Yes, all 7 of our wins with Kane have been against non-playoff teams, but there is something to be said for the effect that he has on our team, and it runs through the lineup.