There were two limitations prevalent for a long time. The four GB download limit and the rule by the EU that cameras with more than 29'59" attracted some serious tax. The EU has changed that apparently and I guess Canon have now resolved the file management issue. As you say, the R7 is supposed to have resolved that.
Never knew there was a file management issue. Only the entry level camera bodies would shut down video recording once they hit the 4GB limit. The camera would seamlessly start recording to a new file.
The exFAT32 file system has a maximum file size limit of 32GB, but most computers cannot handle files that size.