Option 1. Hard forked chain that that pays more to miners
Option 2. Hard forked chain that does not pay more to miners
Users would choose #2. Miners would choose #1
Miners are by definition sellers of bitcoin, users are both buyers and sellers. Chain two would have both sellers and buyers. Chain 1 would have sellers but no buyers, and would therefore have no value. ASIC miners would face the choice to waste electricity mining a worthless coin or shut down.
Options 1 and 2 are different coins, that will have different market prices and different expectations of survival. Each old bitcoin user starts out with the same number of coins in both chains. There is no option for him to take: if he does not spend or sell the coins in one chain, they will simply sit there, as if he had decided to hoard them. He could burn them, but that would mean throwing some value away -- and would make the price of that coin to rise.
So the question is not "which coin would the users choose", but "what will happen to the market price of each coin".
Coin 1 is just the same old bitcoin, with the same network and protocol, minus a reward halving that was scheduled to occur and will be postponed. It will keep working smoothly through the transiiton. Its price may fall considerably, but it is unlikely to become insignificant.
Coin 2 is a brand new coin that happens to start with the same coin assignments, but has yet to build its network. There is a bunch of rich guys out there -- the old bitcoin miners and their investors -- who have hundreds of millions of dollars at stake invested in coin 1, and therefore are quite interested in having the price of coin 2 crash so that it will not steal market value from coin 1.
So, except for the ideologues, if someone wanted to invest some money in "bitcoin" after the change, which of the two bitcoins would he choose?
Except for the ideologues, once the cartel has announced his plans, how many bitcoiners would still wish for the Red Button to be pressed? If the button is pressed, how many will do whatever they could to kill coin 2?
Perhaps, as you say, there will be smart guys who will wait for the cartel to stop jamming coin 2 and then will start mining it, or buy tons of it as penny stock, counting on its recovery. But, if that strategy turns out to be profitable, what would stop other people from forking other Red-Button-style clones of bitcoin?
Note that altcoins are created not because they can be better than bitcoin (which in some cases may be true), but because their creators think: "Why should I buy an existing coin, and see its early adopters become filthy rich at my expense, when I can create my own altcoin, and become filthy rich at other people's expense?"
It seems that you believe that the Red-Button coin 2 will prevail (or at least survive) for a similar reason, namely it would give to ordinary PC owners the opportunity to become early miners of "bitcoin" again, and amass a hoard of "bitcoin" with little cost. That cloned "bitcoin" would have a low price perhaps, but all users of the old bitcoin would automatically be its users too, and (by your belief) it would have a nonzero chance of conquering the bitcoin market.
But, if so, what will stop people from creating more such clones, independently of any 51% threat?
These possibilities with two or more clones of bitcoin are already too confusing for me to reason about them. After all, I am already unable to see why bitcoin would survive in the long term, even with no clones and no 51% shenaniigans. Lucky for you that your beliefs a priori exclude the possibility of protocol changes, 51% attacks, hard clones, and anything that might be a problem for bitcoin.