Who else in the market spun off their fabs? How long will Intel be tied to their fabs, paying underutilisation charges? What's the difference?
Nobody else in the industry has spun off their fabs, therefore you can't compare anyone else's circumstances with AMD's.
How can you NOT be aware of the fact that multiple IDM's have spun of their fabs over the years?
Freescale (fabs spun off from Motorola)
NXP (fabs spun off from Philips)
Infineon (fabs spun off from Seimens)
Qimonda (memory fabs spun off from Infineon, leaving logic fabs at Infineon)
Spansion (spun off from AMD...without being contractually obligated to purchase all future flash from Spansion )
Lucent (fabs spun off from AT&T)
And those are just the big-name spin-offs, not counting the number of companies that have gone fabless or fab-lite by simply selling their fabs outright to an existing IDM or foundry without becoming enslaved to their foundry for a decade plus. (TI selling all of its memory fabs to Micron for example, without contractual obligation to buy all future memory from Micron)
The difference between AMD spinning off GloFo versus the other companies above is that AMD was forced to negotiate from a position of extreme financial weakness owing to the disastrously wasteful acquisition of ATI.
Once the ATI deal imploded in terms of value and profits, AMD truly had no choice but to sell the fabs and this meant they had to sell them on the buyers terms under the least favorable (to AMD and AMD's shareholders) circumstances.
Had AMD the vision and foresight of knowing they needed to spin-off their fabs then they would not have waited for their merger with ATI to start the process. Instead they gambled big and went for broke, and broke is pretty much what it got them.