The value of team depth really depends on how good your stars are up front. Let’s say the average star player scores 40 goals, but considering there’s only so many elite players to go around the league your top line is assembled of really good 1st liners capable of scoring 30. You would be wise to use the money you would save on a star player to get the extra 10 goals somewhere else in your lineup.
So if you have a top heavy team like Edmonton, yes it would be best to save your money on your 3rd/4th lines perhaps spend it somewhere else like defense. But when people are saying Edmonton needs secondary scoring they are talking about the other 4 forewords in their top six. McDavid and drai had monster years last year and Edmonton finished 20th in goals scored. It would have took an extra 30 goals to just be ranked 10th. Furthermore according to
https://www.hockey-refere...e.com/teams/EDM/2019.html league average goaltending last year was .905(which I’ll admit still isn’t great) and average shots against is 2579. For comparison Edmonton received .896 sv% on 2599 shots finishing 7th in goals allowed. If Edmonton gets league average goaltending they allow 24 less goals and sit 15th in the league in goals allowed. Good enough to be a bubble team maybe squeak in the playoffs. On a side note the 20th ranked team in goals against was minnesota. They received .904 goaltending but only took 2419 shots against.
Also Colorado the team to take the last playoff spot finished with 258 GF (10th) and 244 GA (16th)
So that’s goaltending, offensively Edmonton’s shooting percentage was actually .1% higher than league average at which rate they scored 229 goals on 2392 shots. The league average is 244 goals on 2579 shots. With only an extra 24 shots allowed sure you can say the goaltending should have been better, but with 187 less shots taken and a CF% of 48 shows that the roster assembled that includes these 2 top players in the league (which 100% were not the problem) was the bigger anchor to the team.
As of late it seems they found a strong trio in drai-rnh-Yamamoto, and mcdavid being mcdavid they may have the beginnings of enough depth up front to be considered a guaranteed playoff team let alone a contender. Could probably still use a proven top six foreword with mcdavid instead of Neal or archibald. But banking the success of any team all on mcdavid/drai and goaltending with no support would be a mistake. If you shutdown those two or their goalie poops the bed they’re cooked.