I think this potentially damages Discovery more than it goes Sky.
Sky as far as it's concerned is the largest platform for Discovery content - but any removal would reduce reach dramatically. Virgin and BT aren't anywhere near the numbers that Sky have.
Not even having Quest, which is largely successful on the Freeview platform, would prevent any reduction of reach.
Quest is apparently not on the at risk list.
Note, Sky sell the advertising on Discovery's channels so might be a bit of an own goal here.
Noticed it on the Keep Discovery FAQs - Quest isn't listed. It's almost all Discovery channels, as well as Eurosport, that are getting pulled off Sky.
Their overall reach will fall, even if they've got Quest doing very well due to Freeview carriage.
Part of this really seems to be Sky trying to squeeze channel owners' carriage fees while overpaying for the PL rights.
"Winner Winner Chicken Dinner" - PlayerUnknown's Battlegrounds