That honestly hadn't occurred to me before. I had assumed that efforts to force the EU to spend more were just coming from a desire to possibly reduce (or repurpose) our military expenditures....or perhaps just coming from a general sense of "unfairness" that they're free-riding. I hadn't thought that one motive that conservatives might have for pushing Europeans to spend more on defense is that it might undermine their domestic economic model in favor of one conservatives more approve of.

Is that something that's out there? Or was that just something that just flowed out of our discussion?

No, at least not from me.
France and some other European countries have a debt-to-GDP ratio that's greater than 100%. So do we. The trajectory of spending that the Europeans, and us, are on isn't sustainable. Sooner or later the "Guns vs. Butter" choice will be made for us in the form of severe austerity, and no one wants that.

Already here in the States our debt service payments have surpassed our national defense spending.
cbsnews.com - Federal debt interest payments defense medicare children
Federal spending on interest payments is forecast to hit $870 billion this year — exceeding the $822 billion that the nation will spend on defense in 2024, according to a recent analysis by the Congressional Budget Office. This year's outlay for interest payments represents a 32% increase from last year's $659 billion in interest expense.

Ouch.

My recent stridency on this topic comes from one source:

There are those in the federal government that believe that China makes its move in 2027. I won't say where I've had that related to me; just know that there are people at high levels who think that the Chinese are strategically ready to make serious moves against the United States in that timeframe. Will it be 2027? Maybe not - the recent scandal they had in their Strategic Rocket Forces...

csis.org - Chinas waterlogged missiles dont matter
On December 29, Xi Jinping removed nine top military officials in what is being called a “purge,” including officials from the Strategic Rocket Forces that oversee China’s nuclear-armed missiles. Subsequent reporting by Bloomberg indicated the purge was due to “widespread corruption” that has undermined “efforts to modernize the armed forces and raised questions about China’s ability to fight a war,” according to U.S. intelligence. Specifically, Chinese missiles were allegedly filled with water, rather fuel, including many of the missiles in the silo fields recently discovered by open-source intelligence.

...may mean a delay of a few years in their plans.

Summing up:
-The world is headed for a potentially spicy place in 2027-2030ish
-The US is in the worst shape financially it's been in since the Great Depression
-Our European allies have not invested significant amounts in their defenses since the Berlin Wall fell. They're starting to react, but need to do more.
-The Europeans also have financial problems of their own -and- their economies are not oriented towards growth (that's another thread).

So in short
-Time is of the essence, and we don't have much
-The Chinese threat is real
-Every dollar we have needs to be maximized
-Our allies need to have strategic focus. The war in Ukraine, while tragic, isn't the main event. The main event will take place out in the Pacific and will likely start with a Chinese move against our communication assets in space coupled with cyber activity.

The Europeans with their high energy prices, misguided adventures in green power and general levels of de-industrialization need to dig themselves out of a very big hole. Look for the Germans in particular to start up a bunch of their of their nuclear power plants.

So what might China do? I'm not going to phrase this in terms of a prediction since somebody will screenshot this and use it to be inflammatory later, lol. I'll think that up and post it later.