"it's" vs "its": what happened lately?
I doubt that the average person makes significantly more apostrophe-related errors today than they did five years ago. However, you may be noticing an uptick in such errors due to some combination of the following reasons:
The proliferation of informal online content. I think it's safe to say that today there are more blogs, discussion boards, and other websites created and maintained by non-professional writers than there were 5 years ago. Consequently, a a random page on the Internet today vs. one from 5 years ago is more likely to contain grammatical errors.
Confirmation bias. Once you get the germ of a particular grammatical error in your head, you are sensitive to it, seeing and remembering it more often than you otherwise would.
Texting norms. People text a lot more today than 5 years ago. When texting, adding an apostrophe usually requires a couple button presses, thereby slowing down the user. Consequently, texting often forgoes punctuation marks, including apostrophes. One can assume this behavior would translate onto the web.
My iPhone offers me "it's" in all circumstances: I have to reject that to get "its". Assuming other iPhones behave likewise (and perhaps other devices too) that would seem likely to account for the proliferation.
I don't think that it has gotten significantly worse in just the last few years. The vast majority of people writing today were also writing 5 years ago. That said, it has almost certainly gotten worse over time, as book-reading has declined and grammar has been de-emphasized in primary education.
Apostrophes are notoriously confusing for people, and the default seems to be, "When in doubt, stick it in there." I see things like CD's and DVD's all the time, for example.
I think in your case, you have become more sensitive to the error as you have become more aware of it.
Another component may be the proliferation of weblogs and other informal outlets, so although writers have not gotten materially worse, we have been consuming an increasingly large volume of informal writing, thus encountering the error with greater frequency.