The problem as far as prestashop os concerned is the following: From some 20 to 30 modules at the beginning prestashop filled it's module listing with more and more modules. Helpful ones and lots of non-sense-modules as well. The module lists are coming from the /config/xml directory and there from multiple XML files. These XML are updated frequently, so stripping them only helps for a very short time. To get rid of the 290 modules you needed to make changes on multiple files in prestashop core. Search for file_put_contents in the core code.
