Yeah, the whole Steinway mystique thing is most certainly BS. My take is that Steinway makes good pianos - very good. They aren't all everyone's taste, but they are well designed and well made. But they aren't the only game in town!
The big trouble with generalising - Steinway this, Bösendorfer that, pianos made before 19xx the other - is that pianos are individual things made largely out of a living material (wood) and they all have very different lives - different environment, amount of playing, care and attention, regulating, revoicing and so on. Steinway's big selling point is that the pianos never fall below a certain level (obviously, unless they've been badly maltreated), but if one is talking about the finest levels of detail at the highest level, not every Steinway is 'perfect', whatever that means in such a subjective context.
As regards finding your own piano, this simply means being patient, trying different makes, models and individual examples, and then picking one and growing old with it. As regards playing in public concerts, I just think it's part of the fun, finding a piano there and figuring out what one can do with it that maybe one couldn't with last night's instrument.