I think hiring will continue.

The Venn diagram for pilots who both want to work past age 60 and can hold a medical is probably relatively small.

Also due to ICAO rules 65+ pilots would initially be limited to domestic ops, so any seniors who stay past 65 will need to move to domestic fleets... that could create churn on narrowbody fleets but it would be offset by vacated WB opportunities.

The ICAO rules create a wildcard: Can airlines require that a pilot be able to fly to all destinations served by his fleet? Even NB's go to CA, MX, etc. Will airlines have to accommodate seniors by intervening in their schedules to keep them domestic? Can airlines refuse to employ seniors since they can't fly international? Can airlines require that seniors bid around international? Some of this might have to get hashed out in court (age discrimination, reasonable accommodation), or it might be specified in whatever law raises the age. All these issues go away when ICAO raises (or eliminates) their age limit.