maybe i’m just dense, but i’m not following youth logic or your math here..
numbers have been officially reported at two intervals: 60 million sold as of January 2013 [1], and 100 million as of May 2013 [2]. both points indicate its performing fairly well, and just shy of its predecessor. while not ideal, achieving these volumes is most certainly not so catastrophic that ‘investors’ are getting worried. if anything, they appear to be rewarding the company for taking steps to adapt early-on (relatively speaking).
as for sales needing to be higher following a successful release, that’s most certainly not true as a general rule and in this particular case doesn’t make sense either. we're not talking about movie release.. a PC (and, by extension, Windows to most) is a utility, not a discretionary good. most people depend on it in some form or another and if their PC isn't performing adequately to accomplish some task, they upgrade; if it’s fine, they stick it out until need be.. in the case of Vista to 7, many people were plagued with issues and in-need of new PCs (and a more stable OS), hence the rapid rate at which it sold. today, a PC running 7 from a few years back is still fairly capable and the need to upgrade is less pronounced. that it especially true if people are spending less time on a PC as many consumption-related activities can be transferred to other devices like smartphones and tablets.
speaking of which, keep in mind how much has changed since 7 was released.. people are now holding-on to their PCs for longer periods of time and there is increased competition from tablets and smartphones. the market is in decline, i’m not arguing against that, but pointing to 8 as the culprit is inaccurate.
[1] http://blogs.windows.com/windows/b/bloggingwindows/archive/2...
[2] http://blogs.windows.com/windows/b/bloggingwindows/archive/2...
edit: sales numbers are never that comparable, and its been three years.. for all the reasons listed above, they're not comparable.. introducing surface into the mix also makes them less comparable..
my point has less to do with specific milestones and more so to the point that by no reasonable standard could you call the product a failure so far. and projecting your particular dissatisfaction with the changes made (or maybe just a general grudge against the company, i don't know?) to the 'masses' is inaccurate and doesn't add any real value.