I think that number is more like 50%, maybe even less. Phillies base was just 10,000 last season and 15,000 this year. Though I guess that includes all accounts so yeah if they let all the half-season people buy for every playoff game and the partials buy more than one (which they have so far, must not automatically) they probably do get pretty close to 30,000 quickly. I don't think there was even a public on-sale for the wild card round.
Anyway, all the things are true with Tampa. They don't have enough season ticket holders, and a lot of people weren't going to buy tix or be able to go once those times were announced. And the stadium and the location still bad. The new stadium will probably be a better experience as well as an attempt to create a new entertainment district. It still won't change the reality of the location but that doesn't seem to stop Arlington or Gwinnett.