You keep arguing like the choice is between a Relief Line to Don Mills but the OL will only go to SC? It is 100% the case that OL sets us up to get to Don Mills much faster. Again, you argue the capacity is drastically lower when the difference is <20% . . .
You keep arguing that it needs "sufficient" capacity without just saying what that sufficient capacity is, is the train length really the only issue you have with this project?
See, we go from "automated 100m metro trains will be saturated instantly" to, "we should have just run trams down the street!"
Adding capacity beyond what is there increases project cost and likely a fair bit, why not save the money now and build more lines; covering more people and providing higher overall network capacity. There is no need to have a line be equal to capacity to Line 1 to achieve significant relief, the OL corridor while important does not have the same level of density or regional importance as Yonge and will not need the same capacity as Yonge (possibly ever).
I get that you seem to support the idea of a OL as long as the trains are longer, but given extensions North are clearly in the cards I don't think they'd be building a line that couldn't handle the riders for the foreseeable future.
It isn't impossible, the Rockets use their space quite inefficiently
Proof was provided and somehow you still don't believe it, is there any point?
BRT not LRT