You're concerned? Oh dear, am I ever in trouble!
I understand perfectly where you're coming from, I'm the same except I like the late 60's and early 70's stuff. My concession to "modern" B&O is my BC8500 and BG3300.
To my ears, the old stuff performs - and then some. Sure the speaker cabinets can be intrusive with their size, and the pre-dome tweeters are somewhat directional, but these factors are outweighed for me by the looks and the "ear-friendly" sound. I auditioned a BS4 and BL9 and although it sounded great it didn't exactly beat my existing kit hollow.
Reliability hasn't been much of an issue. One BM1000 had to be serviced by Tim Jarman and it has been perfect in almost daily use ever since. A BM1001 is used daily - no probs. Only issue in a small collection of vintage kit in constant use is a BG1202 motor, giving me enough grief to make me consider swapping in proper ball bearings for the old sintered ones. Otherwise everything just keep on going, looking good and sounding better. My Dad still happily uses his 60's B&O too - no probs.
My CD duties are handled by Sony Discman's, recording duties by Sony minidiscs (I use the microphone input for DIN level signals) because they are small enough not to intrude.
80's and early 90's? If that's what you really like then go for it, and enjoy. Some stuff is built to last, some stuff is built to be serviced rather than scrapped, I think B&O is both.
Cheers, Steve