Reason I don’t bother with separate transports and DAC's is because I found that an all-in-one solution is more cost effective.
Until the transport dies and you have to buy a whole new unit. Mechanical equipment like a CD drive tends to wear out faster than electronic equipment. So I have to object to your "more cost effective" claim.
I have a closet full of CD Players from the mid 80’s and 90’s. They all work fine and have thousands upon thousands of hours on them. I don’t think I ever had a CDP fail, then again I never bought a cheep ‘o from Cosco or RiteAid either.
Thirteen or fourteen years ago, to provide a signal for my office's "music on hold," I purchased a "B stock," refurbished or damaged packaging, etc., CDP from the since closed Philips/Magnavox outlet store in Kittery, ME, for approx. $80.00, which was a "rock bottom" price for a CDP back then. The CDP ran 24/7/365 on a continuous repeat for ten years, except when the power went out or the one occasion when we swapped the CD, before the mechanism literally fell apart; pieces of the mechanism were rattling around in the case. My wife complained that we should have purchased a better CDP.
Initially, the CD was a Fleetwood Mac album, but the First Justice of a local court where we worked left me a message that she did not approve of the "hard rock" that was playing on our music on hold, and we changed the CD to Al Green's Greatest Hits Vol. 1, which she apparently found satisfactory. We received many positive remarks about the music on hold, and occasionally a caller would be singing along with Rev. Green when my voice mail started recording. The power of music.