I mean, I hate to be in the position of defending the trot groupings here, but I suppose a) it's not like those 20,000 people would suddenly appear out of nowhere, their joining said groups would be a reflection of a situation where that many people were already looking for ways to fight capitalism and so on, which would already be a good thing and b) as fun as it is to slag the trot groups off, it's not like everything they do is 100% useless and counterproductive all the time, if 1% of those people then got involved as union reps, or in local tenants associations or whatever, I suspect we'd probably be in a better position than we are now.
Just like how, for how big it was, Corbynism left virtually nothing of value behind, but at the same time, I reckon I probably do know more good union reps who came through Corbynism than I do anarchist ones, or indeed non-anarchist but also non-vanguardist and non-Labourist IWCA-flavoured revolutionary socialist ones or whatever.
On the big question, I think a lot of us are agreed about the diagnosis, so the question is what to do about it I suppose? I feel like successful organising at Amazon, or in the gig economy, wouldn't automatically replicate the 1970s NUM or whatever, but it would be a much better foundation to build a project on than anything we have now. And I reckon housing is also a big area outside of work where there's a lot of potential for class organisation that doesn't have to be built around specific ideological lines.
I dunno,
Notes From Below are much too PhDish, and
Angry Workers are utterly tiny and don't seem to have got very far compared to where they started out from, but I have to give both of them respect as being groups who at least try to understand the shape of the working class today and use that question as the starting point, rather than preconceived recipes.