Another way of asking your question is: Why aren't powered speakers popular with audiophiles? Simple, they'd be "stuck" with one amplifier. The thing that drives this hobby (and keeps people employed) is the constant changing, upgrading and experimenting.
Recording engineers need speakers that are accurate. They don't place a premium on imaging and soundstage - just that the speaker is flat enough so it's easy to compensate for different frequencies. Also, their speakers have to reside and perform in a cramped environment so they need to minimize wherever possible. Imagine setting up all your seperates in your bathroom - that's about the workspace of a control room.
Recording engineers need speakers that are accurate. They don't place a premium on imaging and soundstage - just that the speaker is flat enough so it's easy to compensate for different frequencies. Also, their speakers have to reside and perform in a cramped environment so they need to minimize wherever possible. Imagine setting up all your seperates in your bathroom - that's about the workspace of a control room.