Old Classic Receivers: A Mistake to Buy?

I was contemplating purchasing a 70's receiver, as I used to love the construction and appearance of the Sansui, Kenwood, Pioneer, Marantz. However, when I ran this by an audio friend, he said, "Forget it."

He says: They sound terrible. The caps & resistors used before the early 90s' were dreadful. The electrolytics are drying up and will start crackling and substantially degrade the sonics. The switches and controls used were almost never sealed, so they deteriorate and make noise and can't be fixed even by taking them apart and cleaning them.

Tuners: He says that nearly all non-digital tuners used varactors, which go out of alignment and cause problems, so no old tuners, with the exception of the Mac MR-78 and possibly a few others, are worth dealing with.

I am tempted to believe all that he is saying is true, but I see a market for these items, and also know that people claim they are still using these pieces for 25 years.

What's the truth here? Can some of the techies enlighten me?