Mac is on its way of allowing only 64-bits applications. For now, users get a warning saying that the app they are using is not optimized and it opens fine, but eventually, this will be not the case, as stated here:

"At some unspecified time in the future, the operating system will end its support for 32-bit technology… meaning those apps that haven’t been updated just won’t work.

That time, mind you, is not tomorrow, but the company’s hoping that this messaging will help light a fire under users and developers to upgrade before that day comes. Says the company on its help page, “To ensure that the apps you purchase are as advanced as the Mac you run them on, all future Mac software will eventually be required to be 64-bit."
https://techcrunch.com/2018/04/11/ap...t-app-support/

Maybe it's time for that 64-bit version of LOTRO. We know Mac users aren't a big portion of the players but not having that portion might be bad for business.