ubequitein: For the last time! we must do ALL the mitzvohs, but a mitzvah (M) which is dependent on something (P), as long as there is no P THERE IS NO M. not we are not mechuyav, rather there is no M AT ALL AS LONG AS THERE IS NO P!
As for mesorah, THINK for a second, of course there is a mesorah for DARKEI PSAK, but here, the issue about a psak. I.e. your issue is that we have no mesorah that this is the true techelis, the only place we need a mesorah about specific things are by birds. But of course for כללי הפסק we need a mesorah. In short HOW we pasken we need mesorah WHAT we pasken has no meshorah.
As for the Gedolim, the issue is not that it is a hard topic, rather it touches issues that pertain to zoology, biology, botany, chemistry, archaeology, dyes among others. Most gedolim do not have the expertise in these fields, nor the time to get acquainted with it, But the ones that did do wear it such as R’ Belsky ztz”l and lbcl”c , R’ Karp, R’ Nechemya Goldberg