But this just speculation. There's no evidence of any chemical or physiological difference in the meth or from the meth, just anecdotes.
This is exactly what happened with crack. It blamed a drug formulation and ignored the social issues that exacerbated the drug issue. That's why I'm really skeptical about this.
All of this drug's growth in usage has happened after a major recession and then an immediate and drastic increase in housing prices. You also get widening of income inequality and a major sorting of jobs requiring a college education and ones that don't.
Along with a rapid decrease in the price of a drug along with a rapid increase in purity of the drug. The anecdotal evidence could easily be explained by larger dosing.
You can hear a good interview with Quinones for his new book at econtalk:
https://www.econtalk.org/sam-quinones-on-meth-fentanyl-and-the-least-of-us/
But until there's some evidence of different chemistry I'm going to be very skeptical and I think emphasizing the possibility of higher dosing and housing costs along with labor force participation issues makes more sense.