Most people in the speculation forum don't understand anything about Bitcoin mining. The first thing you need to understand is, nobody running a current process node miner actually turns them off no matter what the price does. You're either an ASIC dealer that spent millions on research and design to make it, or some random Joe that paid a big premium for one. Turning them off makes no sense for anyone since Bitcoin is an asymmetric investment. Unless you're mining with crazy expensive electricity, your current generation miner will either pay off eventually, or Bitcoin will go to 0. There's no purpose in turning it off.
While I like your thinking in general, this is a false dichotomy. You're forgetting that miners can and will SELL THEIR HARDWARE. We all know that mining becomes half as profitable overnight when the reward splits. Then likely the price of mining hardware will drop. If the price of mining hardware drops, couldn't the price of coin drop also, despite the decrease in supply? Do we have a good handle on demand?
And what percentage of cash for coin exchange is just miners SELLING TO THEMSELVES to keep the price up?
When I look at exchange traffic and charts, it looks like automated trading to me.I've bolded your last two sentences, above.
You are likely engaged in a bit of fiction thinking if you believe that miners buying/selling to themselves would have any meaningful impact on price or that it is any kind of widespread factor that affects price in any significant way. Further, in recent years, most legitimate exchanges (that affect prices) have various kinds of fees that would cause disincentives to trade with self. The extent to which some of the Chinese exchanges have no fees also cause a dramatic increase in volume, and they tend to not be much if anything of price leaders in recent years (and yes those exchanges are likely heavily employing bots that trade on very tiny spreads).
Employing bots on fee bearing exchanges does not delegitimize the trades, and the exchanges that maintain fees tend to be the most likely to be the price leaders... and even when exchanges allow for a large amount of leverage trading, those kinds of practices can take away (or at least discount) their ability to be price leaders. Yet, in the end, the price is driven by the combination of the actions on the exchanges, which supply of "actual" coins will factor into how much the price changes in one direction or another.