That's a bit unfounded to say the least that it is less-well built. I think scrapped can be read here for departing from fleet. I would be very surprised if it is to be chopped up as scrap.
Many reasons could be from:
A -100 series aircraft, which is more expensive than leasing a -200 due to fuel or better purchase or leasing deal
Corrosion due to environment as mentioned above
Cashflow freeup