Hello @cryptographic,
Extraordinary good article & you highlighted few facts that's why we think twice before invest on mining equipments. Price of Mining equipments, Electricity cost, Net Hash Difficulty makes a complex scenario & average return of investment went 6 months to 1 year in now a days.
If it's not clear by now, I think the sustainability of POW crypto is in serious doubt.
Incredible point you discussed here. Yes, I don't believe POW will remain so long. It's outdated & expired version. Incredible discussion & excellent review you made here.