Interesting discussion......here in the antipodes, Canikon dominate (doh!), but of the 5 reasonably large dedicated camera stores in the CBD, two (which are independent franchises of a buying group) have Pentax enthusiast owners (one guy shoots a K20D, and the other has a collection of film Pentax cameras).
Both praise Pentax gear, but will similarly praise the others (as you have to do in business to survive). They also carry 2nd hand Pentax gear - although thats rare as the OP described.
The other retailers push the canikons and P&S stuff, have no real 2nd hand kit, and I feel have little sympathy for the non-canikons - probably because the staff tend not to experiment or handle all the kit. Its just a job.
I suspect the OPs example was of an owner who experiments and is willing to understand the whole business - not just the high turnover stuff. Full marks to him.
Sadly, these sorts of businesses are vanishing (I can recall a time in the 70s and 80s when we had about 10 camera shops in the CBD). Either the internet and online retailers, or large retail chains are devouring them (eg we have electronics, office products and music retailers with camera depts - some with Pentax BTW).
The net result is sales staff pushing products based on skills other than knowledge of all their products.
I have to admit my guilt here in aiding the demise of the bricks and mortar retailers - I'm buying more and more over the internet - local prices are criminal!
Cheers