Supposedly the word bootlegger came from th fact that smugglers would hide liquor in ther boots. I would think that at the most you might be able to hide half a liter in your boots without being conspicuous. It hardly seems worthwhile unless you were smuggling Dom Perignon, so the questions are:
Did they really do this?
How much would a typical bootlegger make per trip?
I can’t find the etymology of the term bootleg in the booze smuggling sense, but by the time prohibition rolled around, I think a lot of the booze was smuggled in from Canada on high speed cigarette boats, which have considerable more carrying capacity than a “bootleg”.
I don’t think the term “bootlegger” was ever meant to be taken literally with respect to organized smuggling. It is just a quaint term for a concealed stash that was reused for the smuggling trade.
The original bootleggers, therefore, were individuals who hid small amounts of alcohol on their person for personal use.
Other sites suggest that the alcohol was intended for illicit sale to Indians, because federal law had prohibited that. Possibly.
Hip-flasks and other small devices to carry liquor became popular during prohibition. They were not only small but were slightly curved so that they would fit flatly against the body so that the bulge would not give them away. They were sized and shaped to be hidden on many parts on the body, and not just the hip pocket.
Once the word was in use, it was logical for people to use it when the activity was scaled up to industrial proportions during Prohibition.
I have no idea what bootleggers earned in the Old West. During Prohibition, you saw everything from people packing booze into the trunks of their cars to tanker-trucks full of beer to boats of every size and variety filled with cases or kegs. There was never a typical amount or value.
There are a few cites as early as 1885, and they aren’t in any way talking about personally carrying alcohol on your person. They were talking about “bootleg saloons” and such, because there was prohibition in places at the time.