I think Aurora and Anna have the right of it. Most of those authors who I suspect come into your category of 'popular', LL, can also come into the category of 'been here a while'. <g> As such they're not looking for beta readers these days; they're using the ones they always have, going back years.
I do think that the culture has changed over the last few years. There seem to be less willing volunteers to help out authors than there used to be. Which is rather sad. I'm sure that there's a variety of reasons for that though and generalising probably doesn't work to explain it. I've never found that it does really when you're dealing with individuals.
As ever with these things, the board members will have a wealth of reasons why they don't answer beta reading pleas posted here. I do suspect that just sheer pressure of available free time is what scuppers most of them.
Certainly that's my problem these days. I love beta reading and I love helping out new authors especially, but I quite often have to say no when authors send me their stories on spec, because I know I just can't give them the time or attention they deserve from a beta.
One thing I have found though - most of the authors and betas I know beta each other's work and are friends to begin with. You might have more success looking to your FoLC friends first for help. Or, perhaps, you could volunteer to beta for someone yourself. It hasn't been unknown for beta friendships to start that way and for betas to return the quid pro quo once in a while.
As is often the case, helping someone else can often lead to someone helping you.
Although, I understand how frustrating it must be, when you get right down to it though, I think, in the current culture of limited betas, you have to adopt the attitude you have. Write primarily because it's fun and you enjoy it and worry about the grammar and typos later.
LabRat
