Once you are willing to lock the features into stone, it can run on autopilot if the features are resilient enough. When it eventually fails, you design a new currency learning from the past mistakes.
Maybe in theory, but the reality of hacking is that it is also an arms race. You need some reactive protection element or you may be starting again all too often.
POW as an ever increasing resource drain could easily contribute to ruining the planet, I suppose a check might be when it realy no longer makes financial sense they stop. Nice that some POW at least try to create something meaningful that can be used elsewhere, like scientific research.
Talking of integration projects/technologies, like heaters that could mine some of their running costs, perhase this is the best future.
To find synergies and complementary relationships that make the meaningless meaningful and become a part of the process.
Phil