@6ixGod was on point. 7.5 minute service on VIVA was fine, provided that the rider lived walking distance from the stop, and worked walking distance from the stop.
The failing was that most riders did not live on 7, and you needed good feeder services to make the service desirable.
YRT did waste money overbuilding VIVA relative to demand, existing or reasonably foreseeable. But that is not the failing in terms of ridership, its usable service or lack thereof.
That means median wait time, + trip time (inclusive of any transfers and their waits, en route).
You don't need to beat the car in timing, though that's certainly ideal; but you do need a travel time that is both reasonable in an absolute sense and is ideally no worse that the same trip by car + 25%.
The more you climb above that.....the more you need other carrots and sticks to motivate people to choose transit.
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The idea that that a service that appeals to people who currently own a car and commute in said fashion would not appeal to those who take transit is just odd.
A non-choice rider will ride because they lack any alternative whether that's money or age/infirmity or other inability to drive.
A choice rider, by definition has multiple options to make their commute and they will way the attractiveness of both and the cost in deciding what works for them. An unattractive service will fail irrespective of price.