@patur aval assur
My Rebbe, r. Schachter says that the pshat in it comes up once in 70 years means it washes up on shore and you don’t have to dive for it, but you can get it all the time. In terms of mesorah It’s not clear if we lost the source of the dye or the process of making the techeiles [seeing as blue dye was banned]. If we didn’t lose the source, there shouldn’t be a problem to start wearing it in 5774
@hello99. First off I read that rav belsky does wear ???? and second of all, when you say gedolim you are referring to a very specific group of rabannim. There are many great rabanim who wear techeiles; they just dont fall in your definition of gedoli. And you can call me mizrachi if you want.