How reliable is PS audio equipment?

PS Audio did have some build issues in the past when their gear was assembled in China. My Chinese built Premier Power Plant failed within a year of purchase. PS promptly replaced it.  The P5 Power Plant that replaced the Premier is made in the US and was built like a tank as is the P12 that I bought to upgrade from the P5. I see no reason to believe that PS gear has any specific life span.

i just replaced my 31 year old Conrad Johnson PV-12L with a new Backert Labs Rhumba Extreme 1.4.  The CJ was not built to the current PS standards but the only work I needed to have done to the CJ was cleaning contacts on the Selector knob.

Perhaps the "20-year" clock is when PS thinks it needs to be serviced and recapped. Which, in the greater scheme of things, if your hi-fi component only needs to be serviced once every 20 years, I'd say that is pretty damn reliable, especially if it means another 20 years of performance after said "tune up." 

I would say the great thing about a company like PS Audio is that they're made in the US, and you call them up and get someone on the phone, and they can fix it. However, this isn't the case with many companies these days, as we all know.

I have a broken down Sprout. Any suggestions?

No, this is not a question for my GP!

They have a great service department if needed....   Good company, good stuff