My (extremely) rough guess is that there were 150 over-60 guys looking to move back to the front seats when the law changed.
Since then about 100 have moved up or will be.
That leaves about 50 more to go. They can't ALL go to the bus.
Only other problem you may have is them parking or selling busses. If that happens it won't be until 2009. You got that long to build up a war chest or pay down your mortgage into something more manageable.
Or just wait 5 more years for your financial goals, like all us F/O's.....