The two are not comparable imo (and btw I don't go so neutral on this). Different sports, different type of fan bases, many if not most not even from cov.
What it does demonstrate is the appetite if we had ever got it right on the pitch. The fan base swelled by day trippers who want entertainment for their hard earned. United and Liverpool have plenty of day triplets, to sustain large crowds and success you need them. We have a hard core who believe they're super fans and despise the big game attendees and chastise them for Gillingham, Crewe, arsenal and united fixtures in recent memory. Part of the fabric of why we are where we are.
As for franchises don't forget the blaze who are praised on here (another sport I never really got) but I have been to the NFL at Wembley and that's the biggest franchise example of the lot.
The biggest difference with sixfields was the way it was done to spite, when alternative superior, local facilities were available and ripped from us. The distance was not relative, not to me anyhow, it was a moral standpoint not to attend.