well I'm not a soulie but I like the best of all 3 styles, but find the Mickey Champion / Leo Price 'rhythm & soul' stuff the most universally popular and the style that has the most unique and tunefull records - as an R&B DJ, they're the ones I'll pay the most for, cos they'll go down the best. I dont like the stuff that sounds like traditional Rock N Roll much though, but that doesn't mean it isn't R&B - it is, it just sounds a bit anachronistic to me, and you look like my dad at a wedding dancing to it! (sorry rockers!)
That Tiny Topsy is shit IMO, but 'just a little bit' by her is amazing, popular with popcorn fans, mods, R&B fans or students. That's the sort of record you want, whoever it's by : good ones.
Popcorn isn't a style of music, just as Northern Soul isn't, it's the music they like on the popcorn scene, and that includes some crooner and pop stuff, much of which is a bit shit.
I think the 'popcorn' style records that get played at mod / R&B do's are not played by people pretending they're R&B or really worrying about catagories, they're playing them because they like them. I mean, they're from the same era and often by the same artists so who decides where you draw the line, you? I'd certainly rather have a cool and catchy popcorn record like 'Minimum wage' played than an average 'proper' R&B record played. I think it's just average music that's to be railed against, whether it's 'proper' soul or 'proper R&B'. There's a lot of it, it gets played far more than popcorn does, so I'd worry about that more.
Stuff that's popular will get played - stuff that's deemed shit won't for long, whether it's 'real' R&B or not.
I agree though, that too much stuff from the margins - whether it's popcorn beat ballads or gritty harmonica bluesy R&B, which can get very samey for me - is likely to do peoples heads in.