Actually, there is a solution; a PMP (Progressive Money Pot). The probability of winning the PMP is inversely proportional to the Money in the Pot and proportional to the amount you bet. So if the pot has 2 BTC, in it, you should have half the chance of winning it as if it had 1 BTC. And if you bet 1 BTC, you should have double the chance of winning the pot as if you bet 0.5 BTC.  It keeps the pot EV exactly the same, regardless of the pot being 1 or 1000 BTC, and regardless of bet size.

In almost all cases, a PMP is superior to a progressive jackpot and I'd advise sites to consider it (along with the correct terminology, of course)