It is about the ride, sometimes the bike
Excellent musings, Stapfam.
When I'm riding, it is the ride that I remember, not the bike. In our materialist culture, often it is difficult not to apply the constant urge to consume to one's chosen recreation or sport. There have been many postings in this forum & others about the experience of being dropped by, dropping, helping, ignoring other riders whose trappings have all the hallmarks of the consumate consumer. And some connection made between the quality of bike/clothing/equipment and the other person's behavior. There is actually a term given for this but I cannot remember it.
Your evolutionary approach to riding began with a modest investment and has borne fruit. It is interesting that you refer fondly back to that first $ 80 bike and I would venture to suggest that this fondness is not because it was a modest purchase but because of the experiences it brought you. Your tandem brings you a different level & quality of experience and is important enough to you that you've invested seriously in its components, quality & safety. Your MTB has received the same careful attention. Your venture in road bikes has started that same evolutionary path. Whether it becomes your first love and gets the same investment, only experience riding the roads will tell the tale. But these machines bring so much to us that it is difficult not to at least occasionally anthropomorphize, tweak, relate each bit that works, breaks, falls off, threatens or increases our pleasure. That's why I read Bike Forum, for instance, since I can learn so much about everyone else's machine(s) without having to own them all myself, something I'll probably never be able to afford.
At a certain age we learn what makes us happy & satisfied [or we miss that lesson, sadly]. If riding a poor, fair, good, excellent or superb bike provides any one of us with that happiness then more power to the one wise enough to recognize that source of pleasure.
thanks for such a thoughtful posting