Because they have no intention of doing so?
There is a reason why even the ratings of ABC, CBS, and NBC are sinking in comparison to Fox News; and that's because at some point after their initial endorsement of Dementia Joe Biden's disastrous administration Fox woke the hell up and began telling the truth again.
The other outlets, however, continued functioning as the permanent political propaganda arms of the Dem Party; and have totally lost the trust of the sane segments of intelligent people. So it goes.