You said it right there in the 3rd sentence. That's the end state of the Super League. A closed structure with 20-30 teams and all the world's best players, streaming live globally, untethered from national pyramids.
That's what vaults (those) football clubs' values over any other professional sports endeavor. That's what ENIC, FSG, The Friedkin Group (Everton), Kroenke, Glazers/INEOS, etc. are working towards.
I don't want it. You don't want it. But several hundred years of historic record of capitalist systems makes me inclined to believe that the billionaires will eventually get what they want.
And, yes, the NFL and NBA are growing in global popularity. That's even more reason why these people want the Super League. They don't manage the growth of their assets merely in isolated value - they manage it relative to comparable properties (i.e. NFL/NBA teams).
They're not looking at it as though THFC has gained $2.7B ($514M - $3.2B) in value over the past 10 years, they look at it as though they lost £2.3B of value to the Los Angeles Clippers ($575M - $5.5B) in the past 10 years. They're looking at the NBA and considering why a sport with less than 20% as much global support is rapidly outpacing the growth of their investments in the world's most popular sport. And they're going to take the lessons from those observations and apply them to their own market.