How long should components last?

Pretty much forever if well maintained. For example I have Hammond organs and Leslie tone cabinets from the mid-50s that are in like new condition. Same with consumer electronics from the 50s, 60s and 70s; all also like new.

I guess it helps that I'm an old school bench tech with all the proper tools and a perfectionist nature.

Small, flavor of the month, audiophile brands, especially outside the US, are very risky. Stick with well established brands with great track records for reliability and service. For established brands outside the US, make sure the US distributor also has a long, positive track record with in house service techs. Good examples would be Lone Mountain (Las Vegas) for ATC and The Sound Organisation (Dallas) for Rega.

@ghdprentice "I think that about $5K put you in kind of middle ground. Above consumer audio, but in the mid-fi range. So the build quality can be good by typically not great... they use off the shelf subcomponents and stock replacements."

While your statement can be true it can also not be.  Purchasing direct from small quality boutique companies e.g. Finale Audio, Aric Audio and like others you get the build quality, the parts, the circuitry , and the sound to go along with them. For illustration the build list on my  Finale Audio 7189Mk2 integrated amp has Hashimoto output transformers, Hammonds power transformer, DHL Labs Gold RCA terminal, CMC binding posts, Mundorf silver in oil coupling caps, Furutec IEC, QQQ rectifier tube socket, Alps Japan Blue volume control.  The direct to customer price at the time I purchased it was less than $4K.  Eight years running zero problems.   Just one example but it’s not always as your generalization portrays.

The Transformer failing in a DAC is pretty rare.  DACs do not use much electricity.  Of course transports being mechanical fail more often, but, if it was also an electrical failure, I would look at the electricity coming into your home.  You might want to invest in surge protection and maybe a power conditioner.  What about the voltage ?  Does the voltage coming from the wall vary a lot during different times of the day ?  Clean, consistent  power will facilitate your components lasting longer. 

Agree would love to know the brand.   Just a guess.... Ayon?