The look at the text and history of the constitutional history here is informative. I think the text should (anyway does) have some important role here while history (including original history) should (but does anyway) have a more mixed role. History, surely someone with a BA in it and who now helps by writing little historical summaries for a site geared to high school students, is valuable. Decisions are made with it in mind. It just is a changing thing with various moving parts that we can use in various ways.
The text, to be clear, tends to leave a lot of space in most hard questions when resting on that alone. This is especially the case here. It is quite true that only a few things require a supermajority by constitutional rule (the op-ed cites some of the history here) but it also provides the Senate broad power to set rules of proceedings. The fact that only something like treaties requires a supermajority doesn't mean no respect should be allowed to the minority, blunt majority rule always winning. That isn't a good way to do things generally. But, that leaves open a lot of ground.
I will honestly note that during the Bush Administration, I argued that filibustering judicial nominations (at least) could be legitimate. It to me was a way to deal with certain wrongs involving the election of Bush, the two senator rule resulting in a majority of people represented by a minority of senators and the to me overreaching of the Bush side. OTOH, in hindsight, it is unclear how helpful the whole thing was. Most of the judges got through anyway and the precedent hurt President Obama. It is even unclear how much it helped to block controversial legislation. Also, should it?
We saw eventually that the back/forth led Democrats in the Senate to end filibusters for executive nominations (a rule that they never had a chance to apply to the Supreme Court, but Republicans did for Gorsuch). In effect, after years of both sides actually doing it, the whole thing was being used too much for the Democrats. This included Republicans refusing to confirm any judges for D.C. vacancies or to fill an agency that they didn't like. Other basic filibusters like blue slips (which Republicans didn't respect when control changed) also factored into the situation.
The result helped the Republicans fill in a lot of court slots, though there are ways to compensate (there are a lot of senior status slots, already starting to be taken, alone open, but the big solution is both quick confirmations and expanding lower courts). A few abuses of note here -- especially at the Supreme Court level -- very well can be cited. But, long term, this is good policy. Why should those who don't win elections have the power to fill the courts? Leaving slots open for years is abusive.
Then, we have policy. As some have noted, as a whole, even during the Great Society (involving controversial policy), filibusters have not historically been used much to block legislation. Surely, not to the extent used in recent years. The big story there was civil rights, but even there, there was often as much of a majority settlement against them. I think -- without analyzing the data in detail -- one can exaggerate. For instance, national education policy was blocked in part by filibuster as I recall in the post-Civil War period. But, it seems to be the sort of thing that might be used in a limited fashion, but not like more recent assumptions that it takes sixty to pass things.
So, we come to the present. Mitch McConnell at first blocked the rules for a new Senate because he wanted Democrats to agree to the filibuster for the next two years. The Democrats said "no way," but there is constant references to Manchin and Sinema in particular not wanting to let go of the filibuster. Some even fear -- though he consistently has voted for Democratic policies when it matters -- Manchin would switch as if he was some sort of DINO. Sinema, a newer member from the new Democratic state of Arizona, is a more interesting character there. How far will she go?
It's unclear. The first test was the rules. Next, comes financial matters which can appear to be something you can settle via the reconciliation workaround. That seems to be a key approach here -- avoid as much as possible any way to push the point. Change comes over a span of time, people appropriately pushing, but not all at once.
There already is talk that Biden saying he is for "unity" doesn't mean he will just agree to anything to get bipartisan votes. Basic core things will be demanded, details can be negotiated. How far this will go is unclear. We now have a probably not first ten Republican caucus proposal (thus 60 votes with the Democrats) on COVID. The big test might be voting rights.
There is also an argument, one I noted above, about how each half of the Senate are not really equal. The Democrats represent many more people. I think that's valid though obviously that pushes against a constitutional rule. But, hey, the filibuster itself is not found in the Constitution. It supposedly is there to advance the overall principle of debate (ha ha) and the cooling saucer of the greatest debating society and all that. Such open-ended principles can factor in a lot of things, especially when the Senate equal vote rule is so locked in.
When things are so locked in, you usually have workarounds too. A final thing there is that we are realistically stuck with a party in both houses (if somewhat less blatant in the Senate as seen on 1/6) that refuses to do the bare minimum. As an impeachment trial (people keep on saying "impeach" as if it means removal) already starting, the House Minority Leader goes to meet Trump. Can't wait a little bit, huh? Republicans cannot simply even agree (though voting against tabling the question is not technically the same as supporting the merits) the impeachment trial is acceptable. Bare minimum republican values, far from policy disputes, cannot be granted by even some significant limited number of them.
Some would deem 2021 as the true beginning of the twenties. Should be interesting.