I remember as a kid my mother telling me how vegas solitaire worked. Bet $10 and get 80 cents for every card that goes on top (go through deck one card at a time, go through deck only once).
Common sense tells me that even though the house had the edge it was still too slow of a game for the casinos to make money at (having to pay someone to watch you play) then only making <$10 on the deal.
If this was the case, why did they even offer it to begin with?
Have you ever played solitaire in Vegas?
Probably the same reason they offered slot machines, to give the wives something to do while the husbands gambled serious money.
Along the way, slots turned out to become immensely profitable whereas solitaire didn’t, hence solitaire was discontinued.