They might be a new player in the field of online gaming services but they have experience in the gambling industry nevertheless. Aside from that, if a land-based casino transitioned to or have a online casino counterpart then they already have patrons who are willing to spend their money on that site to play.
I disagree. These patrons had already proven the reputation of the casino, they might prefer the physical ambiance but there will be times when these players can't go to the land-based casino, so having an online site where they can access the casino is pretty convenient for them. Besides you are assuming that the marketing team of that casino is incompetent, well I beg to differ. They had the fund to hire professional marketers, so I don't think that promoting a casino to gather players will be an issue.
I don't know with other gamblers, but I really feel that there is a world of difference between a land-based casino and an online casino. Although I don't really stick 100% to either of them, whenever I am in a land-based casino, I cannot imagine the frequent gambler suddenly shifting to an online casino. The experience is far far different. More so to those rich gamblers who have the money to travel and really live the luxury offered in Macau resort casinos.