You can bet on the market going down. Just go to your banker and tell him to do it. The question is just, do you believe it?
Be very careful betting on the market going down. You not only have to be right, you have to be right soon enough.
Saying 'at some point in the future prices might be lower' without a time attached to it is an intellectually empty statement.
[0] https://www.marketwatch.com/story/help-my-short-position-got...