I'm sure that cultural difference from New England makes a difference in how things go.Most of the riders i know ride with others in social groups regularly (and have all sorts of bikes), but practically never attend anything that could be called a 'mtb event'. Me included
With the exception of a couple fundraiser rides a year, if there's going to be a big crowd doing the conga while nuts-to-butts on the trails (my general experience at the 'events' I've been to) , I'm heading somewhere else. 😄
Haven't the slightest clue what a 'tweed ride' is.
Of course, I'm in New England, and people in general aren't so much 'joiners' as they are in other places.
Most of my mtb event experience is from Indiana, where the bike community was pretty small. Most of the events I was referencing were either club fundraiser events or races where the spectating area is just a big party of sorts. Some of them involved bike rides, too. One ride I did occasionally was an urban full moon ride that was generally more about drinking cheap alcohol by a bonfire under a bridge (or brewery hopping) than it was about riding bikes, but the idea was that everybody attending rode bikes there, and they all ride whatever they've got.
The tweed ride I was referencing is similar to this:
it's basically a British version of this:
Eroica. Eroica Gaiole, Eroica Montalcino, Eroica Dolomiti, L'Eroica, Nova Eroica, Eroica Britannia, Eroica Limburg, Eroica Germania, Eroica Hispania, Eroica California, Eroica South Africa, Nova Eroica South Africa, Eroica Japan.
Where I live now, there's a bit less of those sorts of things, but more people ride bikes in general. It seems that most people have smaller groups that they tend to ride with or they are mostly solo riders. Haven't met any people here that I'd call retro grouches yet, so I dunno where/how they fit in with the local cycling community.
There's one bike org in town that does a few themed social & casual urban rides throughout the year. I've done a few of them, and they're generally a "run what you brung" sort of thing.