Why would they bother with it when what they're doing is way more profitable? They also have a reputation for being the partisan press. They'd have to completely rebrand to get into a less lucrative area.
The long form journalism that the partisan press produces, both sides here, amounts to little more than fan service. It's incapable of investigating things out of public interest without it relating to their kayfabe. MSNBC can produce thousands of hours about Trump/Russia, but the for the Snowden leaks you get a few seconds of a professional talking head telling you how Snowden is a bad man.
The WSJ on the other hand has excellent investigative journalism which is usually well separated from conservative partisan commentary - see Carreyrou as a good example.
There is, but if you're ever exposed to it it's probably in the context of brutal point-by-point debunking. On account of how it tends to be hilariously bad. Like that recent Mules "documentary" from D'Souza, or various Sinclair must-run pieces. Typically they're just very-slanted advocacy masquerading as investigative reporting. Or they take the form of popular opinion-jockeys running special "exposé" episodes that are also mostly or entirely easily-dismissed-with-public-info BS. Collectively, these seem to sate the conservative demand for conservative-flavored investigative journalism, and are all much cheaper than doing actual investigation, especially since you'll always find something to "expose" and there are never any dead-ends wasting time and money (since there's no need for actual substance behind the whole exercise).
If you mean from actual newsrooms, sure, those don't do much investigative reporting, but then there aren't a lot of conservative newsrooms. And it's not like the non-conservatives ones do much, either, with a few exceptions.
They're often good material. But they are way way way fringe. 60 Minutes especially is probably only still around because it would be a public embarrassment to kill it.
I mean, the heavy metal sonic aesthetic is not well suited for Mariachi music. The fact that Metalachi exists and has a following doesn't disprove the hypothesis.