Allegiant = $3.3Billion market cap, not gonna pull a Lorenzo
Offer $$ for pilots to cross the picket line - wanna see youself, spouse, kids, house on youtube?
Contract with other carriers for sub-service - see above for anyone who flies struck work.
So they can't just shut it down & start over, & they won't get anyone to cross a picket line.
What options are left, should it come to that?
I don't know, maybe try actually negotiating?