The concept needs to be able to predict and explain new observations, or else it has no utility and is still essentially just a placeholder.
They first came up with it to explain galactic rotation curves. After that, many new observations came in and the model successfully explained them. To name a few: bullet cluster dynamics, gravitational lensing around galaxies, baryon acoustic oscillation.
Like, relativity, you have to accept and account for or GPS wouldn’t work nearly as accurately as they do.
It is neat that general relativity is used in GNSS, but I’d bet that GNSS could still be invented even if we don’t know general relativity. Engineers would probably have came up with a scheme to empirically calibrate the time dilation effect. It would be harder, but compared to the complexity of GNSS as a whole not that much harder.
There’s no real value in having an explanation (other than personal satisfaction, i.e. vibes) for something unless that explanation helps you to make predictions or manipulate objective reality in some way.
You can make a lot of predictions with Lambda CDM. But yeah they’re not going to help anyone manipulate objective reality. Even so, >95% of math, astronomy, and probably many other fields of research don’t help anyone manipulate reality either. It’s harsh to say they have no value, but perhaps you’re right.
At least let me say this: finding explanations to satisfy personal curiosity (doing it for vibes, as you put it) is different from projecting personal feelings onto objective understanding of reality (the vibes-based astrophysics I was referring to in the meme).
I think we just differ on the terminology of invention versus observation. What draws the line between a well-supported theory and an observation in the end comes down to how tangible you think the data is.