The Around the lower great lakes route comes up as being 20 minutes faster when I punch it up, and that accounts for typical border crossing delays as well as Google Maps takes average speeds into consideration, which makes sense between the two routes as average speeds on the 401 and I81/90 than 11 & 144 in Ontario.
Yes, you risk border delays IF you don't time things right, or fail to check the fastest border crossing at the Michigan end of things, but you also risk road closures on 11/144 which don't have any reasonbly viable options to get around either if they happen. At least with the great lakes option you have plentiful plan B options (Waze to the rescue) if there was an unforseen closure. There's long stretches of both 11/144 with no good alternatives.
Toronto/Cochrane/Sudbury/Toronto also comes up about 75km short of the 1609km required as well, so using Toronto as the starting point you'd have to go to, say, St. Catherines to get the proper distance. That brings it to 16.5 hours.
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The around the lake route is actuallly 20 minutes faster despite actually being almost 30km longer, and if one maintains a better pace and keeps your fuel stops tight, you can easily get that down to under 15 hours, 14 even if you're willing to maintain a more "creative" pace.