Because a lot of the other modules are not popular and do not sell well. If you look at their 1.7 modules they only have 24, but modules like the mailchimp module is not needed because it is free for thirty bees, the 1.6 to 1.7 migrator is not needed, th oscommerce to prestashop is not needed, the zen cart to prestashop is not needed, magento to prestashop is not needed, ect. So its a combination of some are not popular and some just don't fit into our platform.