Why are so many House Democrats eyeing the exits?

The DCCC is projecting confidence about going on offense this cycle, but their members’ actions tell a different story:

• Iowa Rep. Cindy Axne is eyeing a run for governor.
• Ohio Rep. Tim Ryan is running for Senate.
• Florida Rep. Charlie Crist is eyeing another run for governor.
• AOC won’t rule out primarying Sen. Chuck Schumer.
• And House Intelligence Chairman Adam Schiff is lobbying California Gov. Gavin Newsom to appoint him California’s next attorney general

If House Democrats are so confident they will hold the majority, why are so many members eyeing the exits?