When WT were just a 3rd party addon company they could do as they wished regarding the use of other 3rd party products in their addons, which they did. But, once WT moved under the MS tent, their products are now branded as MS, and MS can’t (at least right now) guarantee the G5000 will have embedded charts since they do not have any control over Navigraph.
Again, this makes perfect business sense for MS. If I were a betting man, there will be a native solution for this at some point, but until then the plugin will have to do, or use charts on an iPad or another monitor.