Yer an erse John, but you know that
IMO, we've got a more fundamental issue. What Ali says is bob-on for starters. When we were doing road runs regularly, it was a different time - and remember, most people aren't running about in circa 120-150bhp Elises any more - which you could leather a bit without being so far over the limit it wasn't funny. There are a LOT of 350+BHP lotuses out there now - the V6 cars are a different planet for performance, which simply isn't that fun to keep a lid on, on the road - so yeah, a lot of them get used for track only.
I'm aware that's a massive generalisation, plenty of guys (Steve for starters) have V6 cars for purely road use, etc, etc - but we're talking the numbers game. Even your boggo Elise these days is a 220bhp car (remember when N1 TUT's grenade K was a missile with 190?) and they're only realistically a max 150kg(?) heavier than the later S1...
Secondly - the magic time for SE that you remember was around FIFTEEN years ago. All the lads that had plenty of spare time to go for days out around the country have wives and kids now - yes, there were plenty back then that had families and still did the road runs, but the majority of the numbers on them (if you think back) were either young guys with no family ties (

), or lads on shift work that had other time to spend with families, or retired guys - the majority of the old school road-runners just don't have time these days and there hasn't been much of a new blood invasion (with the changing perspectives on social norms with driving in the last 15 years)
Fact is mate - the golden days of getting a bunch of guys together to hoon about in cars is a thing of the past - yes, as you say, you can still get groups together to do driving tour style events, but the very nature of those mean they're a more planned and less spur of the moment sort of thing - the old SE runs that we fondly remember did happen a lot on short notice.
Also - simply traffic through the site. When the SE forum was at it's height - things like Facebook didn't exist. THIS was our social media. So there was lots of ongoing chat and traffic and run plans and ideas just propagated out of that. It doesn't happen so much on Facebook and the like as it's such a dilute medium - this was focused (well, kind of...). But you can't wind back the clock - the genie is out of the bottle.
IMO, all we can do is enjoy our cars, try to organise things that we'd do alone (if we have time) and hope others want to come along. But the days of being able to jump onto SE and find a run happening in a fortnight are long gone - that's just a fact of the changing nature of things, not a fault of anyone or anything in particular.