I don't think it's happening either, eventhough it should in my opinion. That being said, the Habs could absolutely afford it.
I doubt Galchenyuk is going to get $7.0m...at least, not from Bergevin. If I had to make an educated guess, I'd say Bergevin is open to three scenarios :
a) Signing him to a 1-year deal, at a lower cap (between $3.75m and $4.25m), which would give the organization another year to evaluate him, and allow Galchenyuk to sign his long-term deal based on a new set of stats.
b) Signing him to a Drouin type of deal, which is $5.5m per, 6 years.
c) Trading him for a player he feels more comfortable negociating a long term deal with.
I think those are the options he has in mind. Bergevin has many flaws, but one thing he can be fairly good at is contract negotiations. He's the one who signed Pacioretty at $4.5m, Gallagher at $3.75m and Price at $6.5m. That Drouin deal is also looking pretty good if you ask me, and will look even better if it serves as a base for Galchenyuk.
So Bergevin drives a hard bargain, but he usually gets it done (minus a few deals, ala Plekanec).
Right now, we have roughly $14.0m in capspace, depending on who you're keeping on the roster. Add Galchenyuk at $5.5m, we're at $8.5m, with Plekanec still on the team, at $6.0m. Give $10.0m at Draisaitl, trade Plekanec (with other compensation if you need)...the Habs would still have $4.5m, which should be enough to extend Price next year.
So yeah, they could afford it.
...but they probably won't even try.