the turnstile thing is more complex than you perceive because almost every transit system relies on public funding. here (Seattle) those fares only fund about 10% of the _operating cost_ of the transit per Sound Transit's own reports. not to derail the point, but please do go read your transit system's quarterly reports instead of taking the conclusion of fare dodging for granted. just about every city has public budget reports for their transit system precisely because they are the product of public funding.