The better experience described does actually exist, in London/south-east at least - BA’s Club Europe. Lounge, more space, meals. Quite an extensive Med/sun network compared to decades past.
There is no evidence of there being appetite for a premium offer at scale. Not enough willing to pay for it, or to go out of their way to access it. Why bother, when you can jump on a Ryanair a short distance from home at Exeter, Norwich, Teesside etc