Like any electronic equipment, there is a certain failure percentage no matter what. MBP is no different. It's just that more than average amount of failure has been observed for 2011-2014 (?) MBP's.
You can't live your life expecting failure, otherwise you won't be able to do anything. Paralysis by analysis as some might call it.
Currently I have 2011 15" MBP. From the beginning it has been connected to a monitor >99% of the time, so dGPU gets used all the time. The only time I don't have it connected to a monitor is when I travel.
I never had any issue until 6 months ago. But got the logic board replaced for free. But that's after 5 years of constant dGPU use > 10 hours a day as my MBP is my work and personal computer. By then you would expect an electronic equipment to fail one way or another.
Do I expect it to fail again? Sure but it may be something different not dGPU. Some day something will fail, but that's life.
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Make sure you get an older version of GFXCARDSTATUS as newer ones cannot be forced to use iGPU.