Head Gasket Replaced!

Hi I have a 95 toyota 4rnr with 207,182 mileage on the car. I have been very good of staying on top of sheduled maintenances along with oil changes every 3 months.

Recently the Head Gasket blew and I have the whole top motor replaced. While the car was taken apart the Mechanic said it best to replace everything while its apart and so he did and after 2 weeks of it being completed today while driving to work I started hearing a loud scretching noise and pulled over. The towe truck look at the engine and said that the fan belt was turning but the fan clutch was NOT, it just stuck! I phoned the mechanic and he immediately came to look at it and said that its the PULLEY that is having the problem.

2 questions:

1) When a Head Gasket jobs is done completely is replacing the pulley are part of that process?

2) should the mechanic of know this? Or is it just a coinsident that two weeks later the pulley is now the issue for the fan clutch not turning?

Lost for words!