Also, there is something called Halacha for a reason.
You don’t need Eliyahu for that.
Building the Mikdash is like any other mitzvah and chiyuv.
Lo bashamayim hi lemor mi yaaleh lanu hashamayma…..
Throughout history, our ancestors always tried building it.
There were dozens of times when we came very close, to varying degrees.
People who say we can’t, are kofrim.
Maybe we don’t know how to keep shabbos either until Eliyahu comes? Etc…..
Study Torah and Halacha, and we’ll know how.
The earlier generations NEVER said: we dont how to do it.
They tried and failed. Ones rachmana patrei….
We must try and succeed!