If they ever announce that they are going to stop charging for Mac Versions it will mean only one thing - they are not going to release any updates for the Mac version.

Yes it does not make all that much sense. Originally they actually had a Mac version and not a wrapper but it was - "bad" is too kind a word. It was so awful they offered refunds.

The wrapper version does need its own testing and QA - which would not be funded if a PC licence covered access on the Mac also. I personally have both licences but prefer to pay on Mac instead of dipping into Bootcamp just because its simpler. It of course means I have to pay double for each expansion but I'm happy to continue to fund whatever "support" for MacOS the most popular MMOrpg is willing to offer until the pull the plug.