Piracy has saved me plenty. I try to try before I buy. Last time I got burned was Doom 3. Played about 4 hours and hated it. Have not played it since. I downloaded Civilization 6 and what not pleased with it. Deleted the game and saved myself $59.99.
Though consumers want demos, it is not financially wise for publishers to release them. If a consumer tries a demo and dose not like the games, then that is a lost sale. If the consumer has to buy to try and the consumer hates it, then the publisher got their money and another pissed off customer