The pendulum didn't swing back because the left exercised power, it swung back because of what that power did. Bail reform, mass immigration, trans kids, "minor attracted persons", covid lockdowns etc. People were furious with the results of their policies. They didn't go "well the left had their turn, now it's the right's turn" this isn't a schoolyard game.
The pendulum isn't real, it's a made up concept, and there are plenty of examples where it doesn't happen. If you're too scared to use power to go after your enemies because they might do it to you (they already do, they're literally shooting at you and trying to put you in solitary confinement for decades for protesting them) then you should just lay down and die. If you don't want to defend your family by any means necessary against psychotic leftists who want to trans your kid and kill you, then you don't really love your kid, and if you can't even stomach the idea of a few bloodthirsty antifa rats getting fired from their cushy jobs then how will you stomach doing what's necessary in the future? Get a hold of yourself.
There does seem to be some fairly rigid cycle, some pattern to history.... but you are right that it's when the brakes slip or the gas is applied that the wheel spins. Policy and maybe even more importantly the 'happenings' that inspire policy are the forces that spin or hold the wheel but the direction seems to be fixed, there is no reverse, there are no turn-offs.
The lefties actually understand this, Zinn with his famous "You can't be neutral on a moving train" line comes to mind, they brand us as 'reactionaries' and they are not wrong. The left accelerates and we brake, fascism is anything that opposes them, it's true because they will make it true. They will push and push until you have to oppose them and then turn and call you a Nazi. They are trying to put us into checkmate by preempting history, they think that if they demonize fascism hard enough and use modern tech they can halt the wheel. They are constantly looking for the next person that might stop them and branding them Hitler 2, 3, 4 and 5. They make you hear about the camps over and over but never Weimar... because they know once you learn who Huey Long is that the jig is up, they know once you hear Hitler in English you are going to have questions they can't answer.
They don't realize that you cannot avoid the rough terrain ahead, the torque will just build up through inflation and austerity until traction is lost and the wheel slips, smoking the tire and turning it with great rapidity.... or maybe the people at the top do understand and they are gleefully watching their useful idiots get ready to drop the clutch and drive society into the wall at full speed.... or they are getting ready to ship these kids to the South China Sea or some desert fox hole to be ground up in the third great war.
Democracy gives way to Democratic Socialism (see FDR), gives way to Communism, gives way to Fascism. When you start to understand the 20th century you realize that once a cult of power/ideological collective takes over it cannot be expelled through democracy, through libertarianism, etc. Only a new cult of power designed specifically to counter the old one can dethrone it. It is the ideological arms race of history. All fascism is reluctant, is out of necessity, that is the open secret of the 20th century.... it's the only place to go when random brain-rotted furfags start shooting at the debate captain and your political class is a self serving oligarchy with an average age of ~60.
The fundamental question of our time is when does it become so bad it's worth trading your future and your free will to stop?