Since the current process of allocating and producing an Olympic Games is fiscally unsustainable, it is worth exploring some alternative arrangements for hosting the world’s largest sporting event.
Currently, the process of allocating an Olympic Games involves cities producing official bids that outline their plans for hosting the prospective games. These bids are culled over several rounds until a host city is selected—about seven years prior to the start of the Games. This particular allocation process predicts both escalating budgets as well as vote-buying; both of these outcomes occur with each allocation cycle.
In order to reduce the losses due to escalating budgets and vote buying, there appear to be three broad alternatives to the current process:

1) Rotate Olympic Games amongst a fixed number of host cities.

One possibility for modifying the hosting of the Olympic Games would be to eliminate the open bidding process for each Games and, in its place, decide on a set of cities that take turns hosting the Olympics for the indefinite future. College football currently utilizes such a set-up—semi-final playoff matchups rotate amongst six fixed locations. College basketball largely achieves a similar set-up by having host cities generally rotate over the years.
The largest benefit to this alternative would be the budget relief that results from repeated hosting. Right now, every single Olympic host city has to construct numerous venues that, once housing very specific competitions, oftentimes go unused after the conclusion of the Games.
Having repeated hosts would presumably reduce the need to construct obscure sporting venues and, as such, lower the marginal cost of hosting an Olympic Games.  The same logic holds for the public infrastructure improvements that often accompany Olympic hosting efforts.
Further, without the incentive to overspend in order to win a bid against several prospective first-time hosts, budgets could see less growth compared to the open bidding process (though, to be fair, a commitment to ever-escalating budgets could be part of winning inclusion into the host rotation).
The impact on vote buying is a bit less certain.
While the number of opportunities to purchase votes would be reduced—presumably to just one time, when the rotating set of cities were determined, as opposed to every Olympic Games allocation process—the amount of money exchanged could simply equal the amount of money that would have been exchanged over the indefinite Olympic Games awards. (Theory says that people would be willing to give money up to the perceived value of hosting the Games.)
My opinion is that you would have one large, not-too-hidden lobbying process connected to the setting of the rotating hosts—and that is preferable to the continuous vote-buying processes.

2) Assign the Olympic Games to one host city.

This possibility is similar to the above alternative, only taken to its extreme—instead of several cities rotating as hosts, all future Olympic Games would be held at the same location. College baseball holds its championship in Omaha every June; the World Series of Poker takes place in Las Vegas every summer.
Insofar that one set of Olympic venues must be up kept with a single host as opposed to several with a rotation-type arrangement, the reductions in marginal cost are even greater than that of the previous alternative.
Of course, the distribution of these costs falls only on a single host city—but in aggregate, we could expect them to be lower.
The same dynamic concerning vote-buying in the above alternative could be expected to exist here—an increase in the amount of money transferred (though through a single-instance) of vote-buying.
After all, cities are competing for one spot instead of many. My sense is that a single instance of lobbying is still preferable to many—though the sums paid for the “privilege” of hosting the Olympics henceforth could be astronomical.

3) Eliminate the Olympic Games.

Admittedly, there exists no better way to minimize Olympic largesse than to simply eliminate it altogether. Clearly, the oversized Olympic budget issue disappears without any Games to host. Lobbying for future Games similarly evaporates. Further, insofar that individuals made decisions based on the expectation of future Olympic Games, these individuals incur a cost.
Of course, many people enjoy the Olympic Games—so much so that this particular alternative is generally dismissed out of hand. Nevertheless, it would seem at least reasonable to consider the opportunity cost of the Olympic Games—especially of the host cities. Perhaps using these public funds elsewhere might create something that people enjoy even more. Perhaps cutting back on public expenditures and giving that money back to the people would allow them to do something they liked better than the Olympic Games.
We hold tightly to pleasant experiences of the past, and cherish those opportunities to connect to fond memories—but if the nonsense surrounding Olympic finances are any indication, that grip may be just a bit too strong.