I think a lot of s9s are in play...
I am more like sure. Many farms in China have 0.04$ per Kwh rate, if they run S9 on LPM they make .85$ a day or 25$ a month, the old S9s go for about 50-70$ in China, hard to sell / easy to buy. Which means the guys who own them are not willing to let go for less than 50-70$, why? Because they can easily get that much before the halving.
and since there are people with even cheaper power or no power bill at all and the possibility that S9 will become profitable again even after the halving if price spikes way faster than difficulty, it makes sense to keep hodling that S9 rather than selling them for less than the price mentioned aloe.
With Bitcoin staying around the current levels or moving higher, I expect S9s and the like to still be in play until the halving happens, once they retire, people will be surprised of how many S9s were actually still in play and that it wasn't the new gears that making up all that hashrate.
Phill, we seem to be on the same line, the majority of people, however, would think the opposite.