Only SM could provide an answer and then only if they actually have an answer.
Right now there is no real competition but things are changing fast. Personally I think SM has about 18 months to produce the next version of Poser and they better include a lot of new features (like a completely 64 bit version, a better renderer [or better yet a option to use some of the available renderers], better rigging, a clothing designer, etc.). A lot of other programs are getting nearer to the Poser niche and some already have better features in some areas. If Poser does cease to exist I am sure there will be competition for the niche soon. Currently Carrara has most of the features but lacks ease of posing. Blender shows promise and would only need a few extensions (I'm sure these will come but nobody knows when). Daz Studio could develop in the right direction but personally I think they got themselves into problems by building everything in small blocks, they probably need to rewrite a major part of it. Vue is very good at landscapes but relies on the Poser interface to handle the characters, I don't expect Vue to develop the needed features themselves but they could attach to other programs to include the landscape.
Personally I don't expect the existing "professional" packages to enter the low-end market but one of them might to make some money if the going gets rough.

In all it looks like we have to wait for 2 years and see what happens. The takeover by SM doesn't have to be a problem but it could spell the end (they do look a bit like Corel and we know how they treat things they bought). I don't really expect any news from anyone for the next year, most packages aren't due for a major new release until early next year at the earliest.