Unlike a CD player the DAC has no moving parts, one can reasonably expect a 15 year life or more. Think cost per year, think used.

With a good DAC the cost of a transport becomes more or less irrelevant, even $99 CD players show a zero bit error rate and good DACs have a jitter removal topology. I think jitter removal is very important many of the cheaper DACs skip this step forcing you to buy better and more expensive players/transports.

The Levinson No36 DAC was the box that forced people to re-consider the ability of CDs to deliver good sound. A used No36 runs $1,000. Yes this is well outside the budget, but the product was considered a tour de force at the time. My No.36 sounded so good that I ended up buying a 360S for far more money.

Anyway I am a firm believer in an outboard DAC, I've convinced a few people to do this, none have regretted the cost.