New CDP vs. Separate Transport and DAC ???

I keep reading " DAC technology is hanging rapidly". Therefore, is it a no-brainer to upgrade to a separate DAC and transport rather than a cdp? Schiit advertises that their DACs are upgradable, but I lack the technical background to grasp to what degree this might "future-proof" an investment in one of their DACs. Do transports affect the sound at all-- or is that entirely a function of D to A conversion? If the answer is "yes", to what degree does compatibility between any given transport and DAC become an issue? I tried the PS Audio NuWave and it had very little effect on my system (Wells Majestic Integrated, Modded Jolioda JD100 cdp and Silverline SR 17.5 monitors). Does this suggest I need to spend more on a DAC ?  Let's say the total budget is $ 3000. Used is OK as long as I can demo stuff first. I've learned the hard way never to purchase anything I can't try out in my system, in my room.  
Stuartk- I can't answer the question of how much the transport contributes or whether there are compatibility issues, but I when I added a newer outboard DAC to a CDP w digital out there was a definite improvement in the sound.  Subsequently found that upgrading the DAC downstream of my music server also improved the sound.  From what I can read on-line your CDP has a digital out so you can go that route, but, assuming you have the PartsConnexion (or similar) mod, you will lose the tubed output stage.  In my case, when I went from a wireless connection to Modwright Transporter (with Tubed output stage) to USB direct output from my server into a Zodiac Antelope, I felt it was also an improvement, but I also have a tube pre-amp and amp.  The good news is that with a $3K budget, you can get one heck of used DAC. 
swampwalker: Thanks for your response. The mod was done by Mitch Singerman, at Affordable Audio in Venice, CA. I'd have to ask him, I guess. The issue of the contribution the tubed cdp currently makes to the system-- and how to compensate if that circuitry is no longer active-- is a big consideration, for sure, whether I simply add a DAC, or a DAC and a transport. I'd just as soon get away from tubes at this point, so in either case, the gear would have to lean toward the warm side of neutral, like the Wells. 
CORRECTION TO ORIGINAL POST: I meant to type "DAC technology is rapidly CHANGING". 
I don't think DAC technology is changing as rapidly as some want us to believe, and the transport/source is quite important...
I've decided to try out a used PS Audio Perfectwave Memory Player (which I can return) in conjunction with a friend's PS Audio NuWave DAC as a starting point. If I don't like the sound, then I will have to reconsider my desire to leave tubes behind and perhaps find a better tubed cdp to demo.