Make it 10 years, people will still sign on the dotted line.
Maybe a few less, but the left seat of a shiny wide body jet and 9 days off a month seems to work just fine.
FO’s are still scared to call in sick or fatigued because it will impact their ability for command. Add in a few more years on a bond? No problemo.
Don’t worry, after 6 months in the left seat they will sign another 2yrs bond to become trainers!