“Problem gamblers – no one knows how many exist or cost to the state. Labour deputy leader Tom Watson derides admission and says his party will ‘ask the questions the government is failing to ask’” https://www.theguardian.com/society/2017/dec/05/problem-gamblers-no-one-knows-how-many-exist-or-cost-to-the-state
Here is an excellent insight into how the commercial sports gambling operation works by a gambling insider and why the illegal market grows under a system of legalization: https://www.cdcgamingreports.com/commentaries/its-too-soon-to-start-high-fiving-over-legal-sports-betting/
More than six years after New Jersey voters endorsed legal wagering on football, baseball and other sports events, the U.S. Supreme Court is hearing a case that could make sports betting — already a multibillion-dollar illegal industry — legal in the state and elsewhere. Read more here.