Depends what the crew want to do there are tons of 737 and airbus jobs out there for experienced crew.
Even if they do decide to go across its 2-3 months before they will be through the training system and line training never mind signed off.
For those requiring a full type rating instead of differences training (which will be the majority) it will probably be longer. Currently they must a have 3-5 month backlog in training.
it certainly won't cure the problem overnight.