Yes there is a welcome band of young professional musicians but not a new core of young floor singers and audience to maintain the grass roots scene for another generation.

I am more optimistic than that. Floor singers et al are just one way folk music music is presented. It happens to be the format most of us grew up with, but it is arguably not the most natural format. Certainly you would not have found something as formalised as that when Hammond and Co were collecting. Currently the big festivals are very popular. At the other extreme I happen to have just spent an hour singing dandling songs to my infant grandson. Different formats for different situations, that's all. Add to that fashion plays a significant role. It may be all the clubs we know die out then in 25 years or so a new wave of small groups singing to each other arises again. That seems quite possible to me. Folk clubs and folk singing are related but far from synonyms.