That’s incredibly myopic. So dina d’gemara goes out the window. You want a long limud zchus for a previous generation? Great! Kol Hakavod to whoever manages to do so. By daas yehudis (assuming you take such a route), you would be obligated based on where you live. If that’s what is done it is *OSUR* for you to be more lenient.
I have news for you; the mekor for being allowed to wear a shaitel (and not a scarf or other non-attached hair covering) is the Shiltei Giborim. Outside of him, no other commentator was matir. Today, plenty of poskim are matir shaitels al smach his heter – but normatively speaking, he is a daas yochid between the rishonim. He presents a kula (I have no problem with that).
Covering the hair is a *din*.It seems that in your imagination, the only rabbonim that existed before this century were Litvish. The Sefardim wore head coverings, the Teimanim wore head coverings, a fair amount of the chassidim wore head coverings. According to you, there is no such thing as gemara and all we have to do is blindly follow what we see everyone else did before.
Bug checking has always been halacha. Microscopes are generally not necessary if you know what to look for (ayin Shemiras Shabbos, Igros Moshe, etc). If we are newly aware of a new infestation or a new infestation is present, it is osur to eat without ridding it of bugs. You can chose how many lavim you want to be over for eating bugs when an item is muchzak. You would be right if you were to argue that Rav Elyashiv’s chumra re: percentages is a chumra – and it’s not a “normative” chumra either. Yes there is a din of beria, and they are noisen ta’am lifgam b’dieved, but to be mevatel dinim d’oraisa? Oy vay.