OP asked:
“Why can’t we restart the minhag of duchaning every day in chutz laaretz. “
There are reasons mentioned in the poskim, like simcha and the need for mikve. I find those a bit forced. When I have pressed a Rebbe in yeshiva and also the Rosh Kollel from my home town, they both said (at different times) that really there is not a conclusive reason. We just have Emunat Chachamim.