No, you don't get two cups by replacing Kucherov with Matthews.
Yes, and judging by Matthews' mediocre playoff performances, suggesting that he could replicate the insane things Kucherov did is comical.
Besides that, it's not like the years when no one won anything didn't happen. For instance, Draisaitl and Matthews won nothing last year but Draisaitl was clearly much better with his 128pts, so was MacK with his 111 and Kucherov with his 113. Matthews isn't a consensus top 4 player year-in and year-out which is what Kucherov, McDavid, and MacKinnon have been for 3 years. That's why he doesn't belong with the big 4. He's right there with Draisaitl and can be there one year or another but has only been top 4 once in the last two years and twice in the last 4 (and clearly 4th at best this year).