I wonder if part of this problem was the shake out happening, following Covid? That shut down changed a lot of things and some boats were scrapped - perhaps leading airlines to presume that the market would not return for some time.
No surprise that VS did not want to be part of this plan. The Group now have their own cruise line and we may imagine that - wherever possible - pax are on their own airline. Also, now that Delta owns VS, they seem to want all VS craft to be directed to feed into the USA, not feeding another company's boats.
I sit to be corrected.