That's their own fault because they've drug the release of the classic xpacs out for so damn long. I don't like Classic and the misery of trying to find groups in TBC ran me and my friends off. If they had released Wrath sooner without fucking it up I'd of been subbed a long time ago.
I'd be willing to bet they'd like my money more than yours as I'm ok with paying a separate $15 for Classic/xpacs and Retail. Hell if they did the xpacs right and kept going past Wrath and left them open I'd of even been willing to pay $15 a month for each one I wanted to play (Wrath/Cata/MoP) to help support the costs and keep those servers active instead of leaching off a retail sub like it works now.