Python mapscript users have always been overwhelmed when they go shopping in the web frameworks aisle. It's long, and tall, and filled with mildly branded boxes. There's more options than one shop can possibly evaluate, and until the last year or so, none of them made much effort to jockey for the prime eye-level shelf. It's confusing. And the last thing your typical web GIS project needs is more confusion and more choices. You've already had to choose processors (Intel or Athlon), storage (IDE/ATA or SCSI), operating system (Windows, Fedora, Debian, Ubuntu, or ...), RAID configuration, raster tiling schemes, shapefiles or PostGIS, and so on. I really can't blame anyone at this point for taking the route clearly marked "PHP".