My analysis
some time ago suggested that a $20 average fare should just about cover capital and operations cost at 5000 daily riders. I can't imagine that Metrolinx would set a goal of 5000, knowing that would be operating at a loss, given that they've always been very vocal that this was to be a service that paid for itself.
My earlier calculations (I'll have to dig them up) was more based on a 7 year amortization guesstimate, because they need to pay off the trains before electricifation. 20 years is a tad long, I think. I can't find the post at the moment, but IIRC, it ended up being closer to 6000-7000 people at a price closer to $23-$24, based on the figures quoted ($70M operating cost per year including amortization).
But either way, both your and my figures means many empty trains, and that may be an issue with taxpayers who see UPX not being efficiently utilized, and may cause a vote to convert it into something more well-utilized. Cash and Presto prices within $10-$19.99 range probably would provide better utilization and utilize a lot of idling staff at the UPX terminal, including the UPstairs lounge which is probably fairly quiet.
7000 people at $12 average fare ($10 Presto, $15 cash) would have the same farebox recovery as 3500 people at $24 average fare -- there are enough surplus UPX employees to handle a doubling. And 7000 people per day is still only roughly 50% utilization of the current fleet.
An equilibrium of something that causes full 2-car trains during Pearsno Peak but not full 3-car trains. A $10-$15 Presto fare and being a rare standee (e.g. only 5 trains per day of 2-car being standee) is okay with me -- it's not a $27.50 standee fare. Makes a better UPX impression, "wow, look how popular Toronto is, a great business market" -- rather than "wow, not many people doing business in Toronto".
We've got great airport train, it makes little sense to rip it down (even if I wanted it to be like a public transit subway initially). Let's adjust it so it's more useful, make a better impression to our taxpayers, a better impression to businesses visiting Toronto, and fill up the trains a bit more, so that we can at least justify electrification sooner than later.
The 5000 per day goal can break even under running some numbers, yes.
But there's approximately 15,000 available seats per day on UPX. That does not include standees, so with a full 3-car fleet and standee crush, could even go double that (in theory). We do get standees on $10 trains today (GO trains!) and standees won't happen as often as on peak GO trains, so Metrolinx should not be skittish about pricing closer to GO train fares, even if not TTC -- at $27.50 I would be steamed if I was a standee -- but not at $10. Currently, 3250 or 5000 per day will mean a lot of very empty-looking trains even if breakeven at 5000. With 3-car trains and a 10 minute frequency, and lower operating costs of electrification, $10 should still be profitable. (A lot of UPX surveys of Toronto said they'd pay $10, so ridership could really dramatically increase).
In case of capacity issues, there's the option during electrification to run 3-car trains every 10 minutes to allevitate capacity issues. Better to occasionally crowd the 2-car trains (2-3% of the trains) at a lower premium price, to justify expansion.
Even if achieves full farebox recovery, we don't want UPX to be a "perceived boondoggle" that cancels GO RER electricifation, network-wide. For that reason, I think we should, at some point, tweak the fares to reduce the amount of political ammunition available (towards cancelling GO RER), even if it's a bit of short-term "finally"/"see?" humilitation.
For this reason, I think we should make it rocket to 7000 per day quicker, and towards 10,000 per day, as a balance for capacity management (of the infrastructure they chose to build) versus taxpayer impression / business visitor impression.