My town, Indianapolis, manages to integrate most events right into the downtown along with the convention center, hotels, and the financial district. Lucas Oil Field and Victory Field are around the corner on the edge of downtown; that section feels slightly more dead. But Banker's Life Fieldhouse is right there in walking distance and hosts concerts, circuses, Disney on Ice, etc., in addition to the main draw of NBA and WNBA games. So there are multiple events per week, plus conferences and conventions during the week. Plus youth sports events. When you add up the hustle and bustle of weekday office business, restaurants, and all the events, it feels like there's always something going on. Somehow all that fits in a relatively small downtown. There are no expansive parking lots like one might expect for a football stadium outside the city, so that helps the feel; I don't know where people park when Lucas Oil is full but somehow they get there.
Compate the Moda Center Portland - https://goo.gl/maps/pAzRD2rLFRv
with Wrigley in Chicago at the same scale - https://goo.gl/maps/oTKEs75Y7BL2
There's probably 2-3 orders of magnitude more people within a pedestrian mile.
I totally agree with you. It took years for South Beach / Ballpark in SF to become anything that remotely resembles a neighborhood. I remember considering it, briefly in 2008, but my gf decided it wasn't safe enough for her. I didn't like the lack of city amenities.
There is more now, but that's been driven by nightlife chasing after post-work startup people, presumably needing to find somewhere to drink after a rough day :-)