Anyone have good insights on the downfall of TNG-era Trek?

With Enterprise and Nemesis, it feels to me like the kind of situation where all the good people left and the person in charge (or Berman) didn’t know how much their success was because of the good people.

And so they run with their ideas, thinking they’re good and indifferent to the pushback from their underlings.

Is that what happened?

EDIT: So my vague guess as to what would have constituted "all the good people left" would have been Michael Piller, Jeri Taylor (and maybe Ronald D Moore counts too?) leaving. I just checked, and it seems by about Voyager S3/4, they'd both more or less left Trek, and, by the time Enterprise comes around, I'm guessing it was just Berman and Braga who'd stuck around, and, I'd also guess they really didn't have much of a role in giving (or understanding) the TNG era qualities that made it good.

Like, if you take the four series and the people who seemed to have driven their creation and writing (taken from wikipedia):

• TNG: Roddenberry, Berman, Piller, Taylor
• DS9: Berman, Piller, Behr
• Voayger: Berman, Piller, Taylor, Braga
• Enterprise: Berman, Braga

... it seems pretty clear Berman needed good creative minds around him, and Braga just wasn't that person. Moreover, it really looks like it's Piller and Taylor that defined TNG era Trek (or the good parts at least).