In a standard SHU? Sure. You are allowed books and no one is going to ask you to fix their shit every 20 minutes. It's basically $1M for 3 years of work where instead of working you read books and sleep
Yep. I can make that million grow and never work again.
Not solitary, no. That would drive one insane.
That is an overstatement. There have been numerous experiments proving that only unstable individuals might potentially be affected. Latest experiments (long distance space travel ones) placed individual people in a solitary (90 days) and a small group confinement for (500 days) with zero negative effects. You might really get bored, but if you have access to some reading material for example, vast majority of people would be fine mentally, the exception being ones who are pathologically afraid of being alone.
PS. Yes, I would do it. It seems a decent return on investment of my time.
It really depends on the prison. Am I allowed to use the internet, library, gym etc? And do I get my own bed and toilet? If its one of these prisons where I get a ''present'' from behind when I drop the soap while showering... then no thanks. If its like living in a 2 star hotel in solitary without fearing the other inmates, then I might consider it. Its not like $1 million is even that much these days, raise it to $50 million and I would say I'm settled.
Solitary confinement does include reading material, unless an inmate is being punished for some serious violation of prison rules. I do not see anything in the OP about just "dry walls 24/7", only solitary confinement. You must be thinking of a torture cell like this:
They are more of a museum exhibit and scary tales from half a century ago or more. Current solitary cells are more like this:
In case of a backward hell-hole where you still might find solitary torture chambers, in all likelihood they would just shoot you than keep you in it for a year. Also, most death row prisoners are being held in solitary. Some of them are there for a VERY long time (as in more than a decade).