The usual thing is that the market ends up around $0.95 for things like that, if the actors are all solid investors. It only takes one overly enthusiastic yes buyer to break that ceiling, the smart money won't "correct" it down to $0.95

There's another idea, which is make contacts that pay out in shares of an ETF, but I haven't seen this idea put into practice

that's correct. Also Kalshi does pay out interest on, and Poly does on a few markets