If the land based casino do not offer the online version of thier casino, they will soon find thier business lacking gamblers because everyone wants to gamble online while being comfortable at home. Those casino who will not have online web based versions will surely die sooner or later.
However this doesn't mean that they completely end the physical setups, it will be better if they run both online and physical casino side by side. Yes, there will be some initial setup cost but this will soon be recovered as casino start to gain online traffic.
it is true, besides if the physical casino does not have an online casino version I think their profits will not be much because with the existence of an online casino version of course this can make more people gamble and if their reputation is good it will certainly spread by word of mouth about their good and comfortable casino. the existence of this online casino version brings more benefits, because currently the majority of people do their activities online, whether it's work or looking for entertainment.
if they run a physical and online casino at the same time I think the profits they get will be greater because there are two sources of income that can be obtained. although they initially have to spend some money to open an online casino version, I think in the short term it can recover again and they will get benefits forever. it should be noted that currently everyone tends to do everything online including gambling, so if they don't have an online casino version they might not be able to take advantage of current technological developments.