What on Earth are you talking about? You said that the W and Z were ideas that "came from active experimentation". This is wrong. It just so happens that they do exist, however. And that theory correctly predicted them well in advance of their discovery.
You seem to be *ignoring* the "ability" to empirically "test" an idea and verify an idea in a lab, as in your example, vs postulating a purely mythical entity like monopole fighting inflation.

Come on. There is no comparison between these two uses of "maths". One set of mathematical equations can be verified or falsified via active experimentation, whereas the other idea is absolutely impossible to ever find via experimentation.
Sure "you" can. With cosmological observations. Make predictions from the theory then make observations to see whether the predictions match reality. Thats good old standard science.
So if I blatantly "borrow" your math and claim "God did it with inflation", that is a "testable" idea based on pure observation and a wee bit of math?
You don't need to. If magnetic monopoles don't exist (as you keep saying) then they don't need to be supressed.
But Guth used that idea as a justification of "inflation". He seemed to think it was a "big deal" and a key support of the whole inflation concept.
You can't test many things directly. You can test GR though. If GR is a good theory and the cosmo constant doesn't magically balance the Universe exactly then space absolutely must be either contracting or expanding. Its an inevitable result of GR. Observations show its the latter.
The key difference in this case is that I can "experience" gravity here on Earth. I have no doubt it exists in nature and has some affect on nature. Whereas Newton's formulas work very well for interplanetary space travel, I have no logical objection to you looking for a "better" mathematical expression of gravity because I have no doubt gravity exists, and there may be limits with Newton's equations that may prohibit us from fully understanding what's going on.
You don't even understand "zero net energy", how could you possibly hope to test it.
Guth's theory was *not* a "net zero energy" process. It began with *positive energy* in the form of heat. That's a "net positive energy" state from the start. Where did the "zero net energy" idea even come from exactly?
Observations show that the Universal expansion is accelerating.
That doesn't mean "inflation did it", or "elves did it with inflation and dark evil energies".
The placeholder for the thing causing the expansion is known as "dark energy".
So Lambda-CDM theory ceases to be an "explanation", rather it's mathematical kludge involving placeholder terms for what amounts to human ignorance. How then can this theory ever be "better than" a theory based on empirical science like MHD theory and GR theory? You don't actually *explain* anything in Lambda-CMD theory.
So, by definition, if the Universe is accelerating (which we're pretty sure we do) then we know dark energy exists. We can then use our best theorists to come up with ideas for what this "dark energy" really is and use predictions from these theories to test the theories. Good old standard science.
Since "dark energy" doesn't exist on Earth, how about starting with a known force of nature that happens to be 39 OOMs more powerful than gravity? Why begin with a "fudge factor"? How do I "test" "dark energy"?
Er, no. As anyone can see above, things you have said to be untestable quite clearly are testable and it is you who has no idea how testing relates to science.
No. I can "test" an idea like "EM fields caused expansion". I can't physically 'test" the idea that "dark stuff did it". Birkeland didn't just stare at the aurora and say "dark energy did it". He came up with a "plausible" cause based on known processes in nature and built real empirical experiments to test his ideas. Pointing at the sky and claiming "dark stuff did it" is not an "explanation", it's a fudge factoring mathematical mythology based on magic dark thingies.
Come on. There is a significant difference between postulating a real "cause" that might be "testable" in an actual experiment, albeit on a smaller scale, vs. postulating something like "inflation gnomes gave their lives to save us from the monopole clan, while embowering the physical universe with "dark energies" and "dark matter" that keep us expanding away from the monopole clan forever and ever. How does anyone actually "test" an idea that has no less that 7 different acts of faith that are impossible to physically test in a real experiment on Earth?