Well, I think there are some things:
1. Funding
That's really it... and compared to the simple 1 track initial thing COTA had scoped out (which I'm sure the study in itself cost a good amount), a lot of other options are pricey. The thinking is to start off with something small, with the option to later expand it, but I think you're right, something like that causes stagnation in the interest of the project perhaps.
But there could be some really interesting things, like a government entity of some kind promoting it as a green issue, or what about The Nationwide Maglev or some other big corporate sponsor (like the casinos funding theirs in Vegas)... would OSU build one through downtown and then out to the airport, and up to their own airport?
2. Engineering
Probably less important than #1, but still a major factor... with light rail, we have the tracks, with street cars you're maybe leveraging a lot of the existing infrastructure... I always thought use the elevated highways as a bases for a maglev or something, but really all of these kinds of pie-in-the-sky ideas are wide in scope and radically different.
So, there are some things that could make this possible:
1. Ever increasing fascism about global warming would mandate a greater need for efficiency, or open a market for Columbus to earn money by "offsetting" other community's carbon emissions, or otherwise some other kind of major green-is-the-new-black economy shift (2 years?)
2. Some kind of engineering or process improvements that make this equal in scope and cost than other options... this requires it to already be a hit somewhere else.
3. People going whack crazy about the idea, and demanding it a la Marge vs. The Monorail, and we all burst out in song to make it happen.
4. An angel investor or foreign government or corporation that wants to push their maglev agenda.
But ya know, there are a lot of other things in the world that are maybe more important, like poverty reduction, reforming education for an information society, doing something about immigration, etc... and I feel bad to keep talking crazy monorails and stuff when real things need to be done, but that gets into murky waters about whether you really can change the world or not... and "solutions" can be a double-edged sword, sometimes causing as much harm as good. I think its great we're getting a big sewer upgrade 'cause those signs back in the woods at the Park of Roses about sewage runoff always made me sad a little.
I agree that it would be breathtaking to ride a maglev up and down the Olentangy this time year.