Except that's not really how cat domestication happened. Yes, the domesticated cat is a species that developed due to its contact with humans but not ever cat stems from a line that was a pet. For just as long as there have been domesticated cats there have been feral cats and constant interbreeding between the two (and sometimes true wild cats). Cats as a domesticated species are pretty different from every other domesticated species in that the domestication happened more through co-habitation more than anything else. By the time cats became an invasive species to most places, our relationship with cats was, in general, more like our relationship with raccoons than the modern-day relationship with cats (expect we tolerated cats because they kept mice away and we tolerate raccoons only because they are cute). So to say pet owners are responsible for feral cats as a whole is not true and even to say humans are responsible is only true in that there would not have been cats without humans but not that purposeful human action lead to feral cats. VIDEO
