I have two separate thoughts on this thread/issue:
1) The commenters here that claim that only mens sports can be popular because they are superior to female sports athletically...well that's just pure B.S. If that was the case, the ONLY successful leagues would be the top-of-the-top professional leagues like MLB, NFL, NBA, or say European or World Cup level soccer, because everything else would be inferior athletically. Yet, supposedly inferior athletic play is hugely popular in many cases due to competition, tradition, community, etc. Numerous college sports, many minor league sports, and high school sports across the country are wildly popular at times....yet the athleticism is far inferior to the best pro leagues. Popularity is obviously much more complicated than just pure athletic ability.
2) I would love to follow a professional fastpitch team if one was in my area and if the game time atmosphere was fun. I've been to several lower level minor league baseball games that were really fun largely because of tailgating tradition (yes, free flowing beer involved) with gametime events in between innings, etc. I think a pro fastpitch team could be popular locally if going to games were a big event...where that local popularity could spread to other teams and fan enthusiasm would show on TV.
There is another issue I don't know how to properly address here but I'll do it anyhow. I think NPF needs to attract male fans if it's going to be successful. However, in the modern day environment, I don't think I'd be comfortable attending women's athletic events without being accompanied by another female out of fear of being labeled a pervert, creepy, peeper, etc. I always bring my daughter or wife when attending our local D1 college fastpitch games or other big club tournaments. I know occasions where unknown lone males were questioned as to their intentions at local HS aged games. As such, once my daughter's done playing HS fastpitch, I'm probably done attending even though I know the female coach very well. This probably won't be a popular comment....but it's what I feel.
Some good points...
I really enjoy minor league baseball. Our family vacations in Myrtle Beach every summer, and the first thing we do when we pick a date is check the Pelican's schedule. We always attend at least one game while we are there, and sometimes more than one. We also attend some more local minor league games closest to home during the summer. We are also planning to attend a minor league hockey game before DD returns to college for her next semester. These things have been part of our life since DD was quite young. I bring this up because we would definitely attend a NPF game if we could. Just not many opportunities...
DD's high school team was playing an away game this past spring. There was an older gentleman by himself on the first baseline that was taking pictures during the game. The hosting school had two security guards approach him to see what he was doing, not realizing that he was the grandfather of one of the players.