After the destruction of the temple, why didn't we revert to a temporary mishkan?
I read a blog post tonight that started out by asking why we don't have a mishkan today -- we had the mishkan in the wilderness before the temple was built, after all, so if we can't have the temple today, why not revert to a mishkan, some temporary (and possibly movable) place in which the holy service can be conducted until we have the temple again, instead of having nothing at all? The post didn't address the question halachically, which is why I'm not asking the author, but it got me wondering.
The question of temporarily relocating the temple service after the destruction must have come up in rabbinic literature, right? What was the argument against it? I can imagine a few approaches but can't support any of them:
The mishkan was one of the commandments that applied only in the wilderness.
Once a place was designated for the temple and it was built there, it became forbidden to conduct the service in any other place. (The mishkan was ok because it preceded the temple.)
Temporary substitutions for the temple would apply only when Yisrael is together and we're not. That is, restoring the service depends on the ingathering of the exiles. If, theoretically, we gathered everybody but couldn't build the temple in Jerusalem, we could set up something temporary.
A temporary alternative to the temple would be theoretically possible, but we do not descend in holiness and what could possibly be as holy as the temple on the temple mount in Jerusalem?
It would be theoretically possible, except that if it were permitted, people might stop yearning for the temple that we should really be striving for, so half-way measures aren't permitted.
There are issues that would make such a venture difficult, of course, like the fact that everybody is ritually impure (tamei) and so there is no way to purify a new place of service. That will be true when rebuilding the temple too, so I assume a solution exists (though I don't know it).
Lest there be any doubt: I do not have a practical reason for asking. I'm just curious about the approach we take to the question -- was a temporary place for the service intended as temporary from the start and was deprecated by the temple, or are the reasons against it different? Are they practical, like the ingathering point, or theological?