Why does not outlaw introduce passive subwoofers ?
I am currently running a passive SVS subwoofer with an outlaw 7125 amp with great results. Also the potential customer gets automatic choice on kind of amplification he needs ( class AB or D).

The sub market is pretty crowded, so they may not want to get too complex a product line to avoid additional confusion (much like they are keeping their new speaker line pretty simple). For that matter, passive subs have largely faded from the marketplace - HSU no longer offers any, and the only passive SVS's are the cylinders (developed when SVS was new and they hadn't developed a way to mount a plate amp in a cylinder). The powered sub has become something of a staple of home theater, with passive subs being much more rare.

Passive sub woofers are an add-on that make sense when your equipment doesn't have a line level sub woofer output. Of course, amplified sub woofers also accept speaker level input with the same problem that passive sub's do ... the need for a passive crossover network which doesn't give you a choice of crossover frequencies, or speaker impedances.

Why would you want to have the sub woofer amplifier separate from the speaker? The amplifiers that are built into powered sub's are matched to the drivers (if the designer did his job right anyway).

Powered subs integrate other functions such as frequency response shaping and over-excursion protection into their amplifiers. For most people, a passive sub is not terribly useful, and I seriously doubt that there is enough of a market for them to warrant the development expense for a small company like Outlaw.