Blue, I never had this situation, so I a guess I am not answering the exact question you put, but I would evaluate every situation different. For example, say I was the BL in a band were we had a great female lead singer, total package, not a diva, and we were getting great gigs mostly because of her; the only downside was that she was very hard to get a hold of to arrange rehersals and contact regarding gigs. What I would do is ask myself if the hassle of getting in touch with her, and the amount of gigs lost because of it, were significantly more (or less) than the gigs we are getting maybe because of her. I realize that that is an extreme example, and usually the decision would not be so simple, but I would still do it this way.
Also on this topic, the band I have been with in the last ten years does not play full time (we do maybe 4-5 gigs per month), so perhaps my experience is not like those who are playing for a living..... but: I just have not run into a situation yet where a bar or wedding or other venue called us for a gig and because we couldn't answer them in one or two hours we lost the gig. In fact, it seems the quickest reply we've ever had to give was after 24 hours. I'm not disputing that some of you must be losing gigs because a member can't answer a text in 10 minutes......I just have not run into that situation.