Why are DAC's so much more expensive than transports?

To understand DACS you need to.understand the basic modules that comprise a DAC, what they do, and what, if any, impact they have on sound quality. That includes power supplies for both digital and analog circuits, digital input stages including Wifi/Ethernet, the DAC proper, the reconstruction filters, and analog line stages. That's far too much to go into here, so suffice to say any bit-level digital errors are extremely rare, The real ’opportunities’ for SQ impacts lie in the reconstruction filter and analog output stages.

To understand DACS you need to.understand the basic modules that comprise a DAC, what they do, and what, if any, impact they have on sound quality. That includes power supplies for both digital and analog circuits, digital input stages including Wifi/Ethernet, the DAC proper, the reconstruction filters, and analog line stages. Thats far too much to go into here, so suffice to say any bit-level digital errors are extremely rare. The real 'opportunities' for SQ impacts lie in the reconstruction filter and analog output stages.

I find it interesting that we want transports to be "truth tellers", reading the data from a CD, SACD, a hard drive, SSD, or from the Internet and output that data exactly as it was intended, bit for bit, and have reasonable timing in the data to minimize perception of jitter.  Then we feed this highly accurate data stream into a DAC, many of which will reclock the data stream, but the DAC is not a "truth teller". DACs do not all sound the same, some use DSP, in various implementations that affect what the output will sound like, then you have the distinct analog output section choices being made at any price point. There is no way you can say what you are hearing is what the recording engineer or producer heard in the studio when the album was mixed.  You can say you like the sound of your DAC, or the sound of another DAC maybe better. But at the end of the day there is no absolute "truth".  Transports as technology are, as one person noted, almost commodity items, while audiophile quality DACs will likely forever be more costly specialty items, designed to appeal to certain acoustic preferences. I'm afraid what this means is that most of us will have to go through several different DACs in our journey to find the one we simply like the best (at whatever point our wallets say "enough").

As LM3875 chip amps offer the most direct, least colored sound, likewise would TDA1543 chip DAC's be similarity uncolored and direct?

I don't get tired of drinking water. Sure, some flavored beverage is exciting for a week but I know I will get sick of it soon enough.