The tradition of unrestricted Senate debate has been a part of the Senate since the inception of the republic. In fact, prior to 1917, there was no mechanism for ending debate so long as any single senator desired to speak. And given that Congress used to meet much less frequently than it does at present, it was commonplace for bills to be "filibustered" simply because a single senator didn't like the bill, and other more pressing bills (read: supply bills) needed to be taken up before the end of the session. The idea of making someone speak in order to stop debate from ending was even more ludicrous than the idea of waiting out a filibuster (which in itself was ludicrous); it just wasn't even considered as a rational tactic. (For more on the circumstances of this, I would recommend reading Caro's excellent biography of Lyndon Johnson: specifically the third volume "Master of the Senate," where he discusses in depth the South's effectiveness at stopping bills from coming to a vote circa 1957).

As for cloture, in its original incarnation (remember, this was only quite recently: 1917) it required 16 senators to file a petition for cloture, at which point 2/3 of those present and voting needed to vote in favor to lead to a vote. However, presiding officers consistently interpreted this Rule as NOT applying to "motions to proceed to consideration of a bill," which are necessary by Senate Rule (from I don't know when, probably since Jefferson's Manual) for making a piece of legislation the main motion. As a result, if you didn't like a bill, you could still always just filibuster the motion to proceed until the late 50s/early 60s when this loophole was closed. Since there were 3-4 votes between the motion to proceed and the final vote on the issue, a group of 10-20 senators (say, the Southern bloc) refusing to allow a bill to come to the floor was more than enough to kil lit.

My point is this: the notion that the filibuster is a recently parliamentary invention ignores the 80-some-year period from 187X to 1957 when not a single bill related to racial injustice was passed into law at the federal level. To my knowledge, "the South" was never even in control of 1/3 + 1 of the seats in the Senate chamber, but they still managed to effectively use Senate Rules and precedents to restrict these bills from coming to a vote, and I can't think of a single congressional session during this period that was extended to try to outlast opponents of a bill. It just didn't happen.

Today, at least, you can a) get to cloture vote, since the motion to proceed loophole has been closed and b) stand a reasonable chance of succeeding at the cloture vote, since you only need to convince 3/5 of the Senate that something is worth voting on. If there is more technical filibustering right now (by which I suppose one means defeat of cloture motions), then at least there is a public denouement, rather than a policy of simply giving up when a handful of senators express opposition.

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Also, two asides:
1. Thurmond's 1957 filibuster only occurred because he wasn't backed by the rest of the Southern Caucus. They chose to allow the bill to come to a vote, presumably because they knew that Lyndon Johnson (majority leader) needed a civil rights bill in order to be a plausible presidential candidate, and they really really wanted a Southern president.

2. The idea that the Senate Rules are readopted every session has never really been accepted by the Senate. Nixon was the first presiding officer to rule as such in 1953 (it may have been 1955) as part of civil rights strategy, but it was overruled on that occasion and on most later occasions. In general, I would say that the prevailing sentiment among Senate parliamentarians is that the Senate is more of a continuous body, and I would expect a real struggle if a majority ever attempted to pass a new set of Senate Rules under the supposed "normal parliamentary rules" under which the Senate debates at the beginning of each session.