(Disclaimer: I work for shipyard.build so i am biased here..)

Dev-owned testing (or even dev-involved testing) is much more realistic when devs have shorter feedback loops between their code and its deployment. So often i've seen momentum get lost when devs have a wait period before they can run tests/do basic manual testing. Then the test aspect becomes the thing that "slows down" devs before they ship a feature, so they might tend towards shortcuts