I get that money is always going to be an issue but lets compare bottom 6's of other "contending" teams:
Toronto - Domi, Robertson, Laughton, Kampf, Jarnkrok, Lorentz = 11.4M
Tampa - Bjorkstrand, Gourde, Goncalves, Glendenning, Chaffee, Girgensons = 10.85M
Florida - Lundell, Boqvist, Greer, Sturm, Rodrigues, Luostarinen = 14.625M
Winnipeg - Niederreiter, Namestnikov, Perfetti, Gustafsson, Tanev, Barron = 14.9M
Washington - Mangiapane, Raddysh, Eller, Duhaime, Dowd, Beavillier = 13.7M
Colorado - Wood, Coyle, Colton, Kelly, Drury, O'Connor = 15.35M
Dallas - Benn, Johnston, Dadanov, Back, Steel, Bourque = 15.5M (9M from Benn)
Carolina - Martinook, Staal, Stankoven, Robinson, Jankowski, Svechnikov = 16.24M (7.75M from Svechnikov)
Leafs are definitely on the low side but I still think the Leafs have struggled to allocate the limited budget well enough to target players with a role. The Leafs bottom 6 is always just a collection of guys. They never go all in on roles. It's just get some random guys and stick them together.
Kampf is a good penalty killer and an ok defensive player but he's not a shutdown centerman. He's not going head to head with McDavid. Domi has a lot of positives to his game but he's an atrocious defensive player and his offense is unreliable. Laughton/Jarnkrok...are guys. They don't really have a purpose with any of their bottom 6 lines. Go all in on defense only...fine. They don't do that. Go all in on smash and bang hockey...they don't do that. Go all in on all-offense....they don't do that.