It's a bad move.
The airlines can't control the WX nor the government run airspace.
Concur...
ATC lost the bubble when most companies started the code sharing/scope creep crap. CRJs/RJs/Q400s/etc clog up the airspace/runway/ramp and here we are.
Picture being #1-4 at the hold short and, after being in line, having to return to the gate because you hit 3 hours...only to restock on food/beverages, empty the lav, let the pax off who want to get off (+ checked bags), etc......only to get back in line again or most likely cancel.
Aircraft returning to the gate from the departure line will be a huge headache for the ground controllers and will cause more delays. The next time you are in line look at the taxiway runway setup. Not many places have parallel taxiways you can use. The active runway is the only thing around (not full of planes) in a lot of cases.
The good thing about this (assuming it happens) is companies will (should) pass the increased cost onto the ticket price.
Watch companies that operate out of places like JFK and EWR as this sorts out. They will be the first to figure the work arounds out with a PR nightmare to follow.