Just for the record, I work 5 days full time and I am always on-call on the weekends...so my working hours will not be much affected by the change of weekend.
But instead of arguing about a silly idea and trying to make up silly excuses like trade and industry and overseas call centers let's just start by asking "Why YES "??!!!!
What makes a country changes the weekend??? this means a hell of procedures and change in every aspect of the nation's life...what purpose would that serve??!!!