One of the frustrating things about the manicule is what I think is the reason you don't see it used online, and it is "everywhere" only in physical media: cluttered pages/GUIs and low-DPI screens mean that almost all of those manicules you see as scans just don't work as a digital manicule. It's always easier to use some sort of arrow or background highlight or other way of calling attention to a particular line. Note that OP makes no use of a manicule in this web page, and the only web example OP gives is an emoji - which was intended for SMS chat messages (and looks very ugly, even ignoring the color or other issues with emoji). That is probably why it is honored mostly in the breach by contemporary web designers - many more know about it than use it.

Like that gorgeous orange (letterpress, I assume) manicule you see in the middle of OP - that line-work will never work when scaled down and put into a web page as a normal little manicule. The details get lost in a blur, the hand becomes a solid blob of black, it looks goofy and out of place (note: for the mouse pointer, this is a feature, not a bug), or it ceases to look like a hand at all to someone who isn't primed for it by an article.

I can tell you that because I tried one that looked a lot like that. I went through literally hundreds of manicules from Wikimedia Commons, Font Awesome, Google Images, and articles like this, trying dozens of them on my actual website, and it took that long to find a single one I was at all happy with in context. I was shocked. No other icon I use on my site was that hard to find an adequate version of. (We really wanted a manicule for our use-case, so we persevered.)