At this level of high(er) end audio why not offer balanced connections?

My guess would be that equipment that is manufactured as truly balanced, would always have XLR connections.   And all other equipment having balanced connectors are only fooling the buyer into thinking there will be an improvement in sound by using them?  By using XLR cables into an unbalanced amp, does the signal not have to be processed one extra step?  

My tube amps are from Triode Audio of Japan.  TRX-M845 mono blocks.  I asked them directly what type of cables they use when setting up systems at major audio shows.  My thought being they would use what makes their equipment sound the best.  They responded only RCA cables are ever used, as as the amps are not balanced by design.  That's good enough for me.  As for the "long run" cable scenario. my preamp is 18 feet away from my amps.  I have been told by many sources this distance is nothing for an RCA cable.  Now Hegel on the other hand, suggests the use of high quality XLR cables is the way to go.  I have tried both and must say I hear no difference in sound.  Tempest in a tea cup IMHO.