It's not a new thing. PFOF has been a contentious issue for more than 30 years. But, with the rise of feeless retail trading options since 2018, PFOF is back in the news.
Looking into the statistics of gambling is illuminating and depressing. The UK, where gambling is more widely accepted than in the US, sees rates of 40-60% across all adults according to 2016 research. Revenues for casinos are over $100 billion annually, and global gambling revenues, including sports betting and the national lotteries, amount to over $400 billion. That's like the equivalent of the entire software cloud industry. And it asymmetrically addicts and disadvantages the already disadvantaged (see academic research here, here, and here).