> Any reform that cuts or substantially restructures government is impossible with the filibuster.

The 13th, 14th, and 15th Amendments (among other fundamental reforms of government) were proposed by when the filibuster was stronger (unlimited debate with no cloture available) than today. And, again, a simple majority of any incoming Senate can abolish or reform the filibuster to their taste – as they have, both creating it by abolishing majority-vote-to-end-debate in 1806, and then a century later by creating cloture, and then several times since by revising which matters are subject to filibuster and which are subject to debate limited by majority action.

> The fact that republicans don’t eliminate the filibuster doesn’t change my point.

The fact that they can by a simple majority vote proves that it is no obstacle, only at most an excuse, to them when they have a majority.

> E.g. if republicans eliminated the filibuster to abolish the department of education, democrats would use that to pack the courts and impose nationwide affirmative action.

Affirmative action was already established nation-wide, and the Senate already abolished the filibuster for nominees to the federal courts (Democrats did it for lower courts, Republicans for the Supreme Court.)

Which, again, demonstrates that the filibuster is not an obstacle to the majority.

If it’s just a matter of Senate rules, the Senate is empowered to effectively do anything they want under the Constitution.

The real issue is that once you set a new precedent, there’s no going back. The Democrats invoked the nuclear option for Federal judges below the level of the Supreme Court, so the Republicans took that one step further.

Both parties understand that once they use the nuclear option or just adopt new rules at the beginning of the new session of Congress to disarm and disempower the minority because they have the majority, that that same precedent can be used against them the next time it is politically expedient to do so when they are in the minority position.

So the politics matter, because at the end of the day Senators still have to get along well enough with each other to get some Bills passed, most importantly the appropriations bills, not the biggest flashiest Acts of Congress they can muster and nobody or at least very few in the Senate truly want the filibuster gone.

> The real issue is that once you set a new precedent, there’s no going back.

Cloture rules have both tightened and loosened over the history of the Senate, so this is demonstrably false.

If it were only about the rules, you are correct. If it’s about the politics, you might be correct on a long enough time scale, but it’s irrelevant in the short to medium term. Right now we’re in a holding pattern on the cloture rules because of promises of tick for tack escalation between both parties. It’s not as if one party is going to loosen them for themselves for one session of Congress and be able to reasonably expect that they will be tightened up to their benefit by their opponents once they’re a minority in the next session.