In a hard cap league you can't have it all. Even if you get lucky and have a great complete roster due to players by far outperforming their cap hits it's impossible to keep that team together. And if you are going to have a weakness on your roster, a subpar 4th line is by far the easiest one to mitigate since three lines can handle almost an entire game without being overmatched in terms of TOI. So even if you manage to put together a great 4th line it is still a very bad idea to spend money and resources on keeping it together.
Filling it with "young drafted/developed talent" isn't something you can bank on since prospect development is a bit of a crapshoot. This season we sort of did what you advocate by filling our bottom 6 with up and coming players and it was one of the worst bottom 6:es the league has seen in the past five years.
WRT your Tampa example, their roster is falling apart under the cap crunch and they have been paying through the nose to get cheap contracts just for the next season. Though I will agree that they have been as close to a complete team as we have seen in the cap era for the past two seasons, but they won't remain one for long.
Holy cow...in a hard cap league having the young talent on your 4th line is EXACTLY how you survive in this league. You just proved my point.
At some point you cant keep everyone and the middle 6 players that price themselves out of town need to be replaced. THOSE are the hardest players to replace when youve emptied the cupboard for one player in your top 6.
What money are they spending on the 4th line? How much have I advocated spending? Young kids on ELCs is breaking the bank? What resources? Letting your young drafted talent ease their way into the NHL in a limited role on a very competitive team?
For this year’s team, it failed because Howden did not really progress however at the same time he has not been considered one of their premium forward prospects. They also ran the likes of Michale freaking Haley out there at times instead of signing someone like Brian Boyle on the extreme cheap to help insulate someone like Howden. The Rangers other problem is they havent drafted/developed enough forwards in recent years. Part of that is because they stripped themselves of so many draft picks via trades.
I dont understand the critique of Tampa. Theyve been a cup contender since 2015. 6 seasons. So what if they teeter out in 2 years? Thats 7-8 years of a window. Thats incredible. I admire them. They have done things the right way and unfortunately have come up short.