From Wikipedia: "The brothers relocated to Miami, Florida, early in 1975 to record. After starting off with ballads, they eventually heeded the urging of Mardin and Stigwood and crafted more rhythmic disco songs."
Play the Bee Gees 'what if' game if you will. What if they had not relocated to
Miami and what if they had told Mardin and Stigwood to stuff it.
Surely with that much talent they do not just wither away at that
point. But what do they go into? Progressive, maybe? Or do they
wait for the new wave economical/pop song thing to happen again and
get a second wind on their careers as did the Kinks, Hollies, Mitch
Ryder, Iggy Pop, Brian Wilson, etc?
p.s. For some really great disco, try this online radio station: http://www.radioitalo.com/