I'm not sure what you're trying to argue here. Keeping the high speed section to the part where freight trains don't run seems prudent to me.
My point is, Alstom is not actually proposing a Toronto-Montreal-Quebec HSR, only a Montreal-Quebec HSR. It's not clear if or how the two proposals differ outside of that stretch.
You're making a lot of assumptions. The original HFR talks about speeds that "could eventually reach 200 km/h"
. We don't know what speed the section east of Havelock would support. You can't just rebuild the existing line to support 200 km/h, that would require a new, grade separated right of way. If you're doing that anyway then a 300 km/h line isn't much more expensive. At least that's what previous HSR studies have concluded. The number of minutes saved is apparent by the travel times in the presentation.
In the absence of Ottawa divulging its plan, assumptions and speculations is all that we have to work with.
The original vanilla HFR appeared to suggest that the original CPR routing would be followed, with curve banking used as the primary means to raise train speed beyond its as-built values. It was hinted that a limited number of curves might be eased if there was an economic benefit to doing so.
Subsequently, Ottawa has hinted (in response to proposals from local communities) that some amount of the Havelock-Perth segment would be built as a new line. The Ardendale - Sharbot Lake - Ungava portion was thought by some to be the most likely segment as there were adverse impacts to Sharbot Lake, and as that segment is particularly curvy. There is no indication that Ottawa proposes any further new construction beyond that stretch.
If Alstom is proposing new construction or HSR level upgrades for the full Havelock to Perth segment, then yes it will be a lot faster than HFR (and a lot costlier). But without clarity, the relative travel times remain unverified, and we cannot be certain that Alstom's claimed improvements in travel times are valid.. And if Alstom's proposed HSR quality segment is less than the full Havelock-Perth distance, its time saving is less and the proposal is not that much better west of Montreal than HFR's is.
So, again, I am saying it's only superficially better than HFR, and its benefits where they exist are being targeted to the Quebec segment and not spread equally across the full route.