Let's just completely ignore that in recent years, Olympic games have had multi-location (city) events and even other major world competitions (World Cup of Soccer, Euro), did the same.
A) Who cares what FIFA or UEFA does? They're completely unrelated entities who unlike the IOC have had the precedent from their very inception of hosting their events at a national scale. The logistics of infastructure needed for a single-sport stadium-scale event are different from those of a multi-sport event with a wide variety of capacities.
B) There is in fact zero precedent for an Olympics being spread out to the extent being proposed even if it was in two locations, let alone three. This isn't the same level as having your alpine events in a small town a short drive away from the hub city because of the necessities of geography. Moving what is essentially half the events into a completely different province in a completely different time zone on a completely different mountain range - and then splitting whatever events are left with another major city several hours drive away - defeats the entire purpose of a host city. Calgary isn't even going to be hosting a majority of the events by this point. Consider that the Olympic bid coming out of Switzerland, a country that could fit entirely within southern Alberta, has been essentially killed out of the gate because proposed venues would be sprawled out too far - and "Calgary" (even calling it a 'Calgary' hosting bid is innacurate at this point) is now proposing a scheme involving exponentially longer distances. It makes no sense.
C) Let's say for the sake of argument the IOC goes against everything it's done in the past century and greenlights this thing - maybe they'll get forced into it because we're the only ones left who are stupid enough to still bid, who knows? Why not propose it that way from the start? The entire appeal of this bid was supposed to be that Calgary has the existing infrastructure and alpine venues to host on the cheap. Now overnight they're suddenly proposing this monstrosity. If anything it unnecessarily balloons the costs as a whole by dragging another province's budget into the mix and requiring security to juggle between three venues sprawled across western Canada when they could have been concentrated on one and a half within an hour's drive of each other. So how much shit is Calgary in economically that it now finds itself compelled to believe it's "cheap" Olympics is going to be three times too expensive to stomach?
The precedent or lack thereof ultimately isn't the point, the fact it's even being considered at all this late in the game is extremely troubling. It doesn't speak to the kind of economic confidence that would, say, compel a professional team to not cut loose and sell off to bigger pockets down south if checkbooks start getting opened. Especially when this type of bid openly discourages the need to build a new arena.
