Tube preamplifier lifespan

Onehoursepony,

Utter nonsense.  The only thing that does not last as long is the tubes.   There are Mcintosh, ARC etc... tube preamps still in the field.   

exactly , Mcintosh amps last for a very long time, why would PSaudo preamps and amps not last for as long?

It looks like you are looking for a particular answer or opinion that matches your already made- conclusion 

@tablejockey, Paul McGowan told you that a tubed component only lasts 20 years?

With most tube gear, you can expect a MUCH longer serviceable life than solid state gear.  Most parts can be replaced on tube equipment while many solid state gear becomes unrepairable because a chip or transistor is no longer available.  Also, tube gear has far less parts because the circuit is simple.  One of the technicians at a local shop restored a solid state receiver as a labor of love.  It took, among other things, replacing more than 200 capacitors; this would never be done as a commercial repair.  
 

My tube preamp is about 15 years old and has required no repairs nor replacement of any tubes.  Moreover, most of the parts were very old when it was built by a custom builder.  The power supply is new, but the audio circuit parts are up to 80 years old.