Retro television shows have never done particularly well unless they were set in the Old West. Shows set in the 20's, 30's, 40's, etc, any era outside of the one in which they aired have never lasted long except in three major exceptions - Happy Days, Laverne & Shirley, and The Untouchables.
The Untouchables succeeded for a number of reasons. First, the veil that had been on the Mafia for a number of years was slowly but surely being peeled off due to gangland killings and the fame of gangsters such as Al Capone, Bugsy Siegel, Dutch Schultz, Lucky Luciano, and others. Even before the Godfather and its outstanding first sequel, the public had a fascination and curiosity with the mob. So take some true events, ture characters, heavily fictionalize them with Hollywood gloss and pathos, and you get a very successful show that made a star out of Robert Stack and brought new fame to a Treasury agent named Eliot Ness.
The Untouchables' First Season collection should not have been split up into multiple sections. That's greed, pure and simple. But the lure of this show - its great characters, performances, grit and intelligence will draw buyers even though they know they're being ripped off. Stack's Ness is one of the best alltime detectives - fearless, relentless, and absolutely ruthless with the bad guys. His politically correct team had everything but a black guy (which would have really stretched believability too far), including a white guy (Hobson), Italian (Rossi), Native American (Youngfellow), and Jew (Rossman). The supporting casts were always excellent, and Bruce Gordon brough the right amount of humor and menace to Frank Nitti, Capone's chief lieutenant.
The Untouchables - Season One, Volume 1 is not untouchable, but it is irresistable.