https://2.bp.blogspot.com/-kVZBzYB-bm0/WRtS7XW0nqI/AAAAAAAAlTA/H0Asf1YvUAAoucP6tb2fZ9loABGqa-ouQCLcB/s1600/427eba58bd72a7eb.jpg https://2.bp.blogspot.com/-ARVXxODOC2g/WRtS7a8WggI/AAAAAAAAlTE/pMEN-riIYTIlBI1qGHO-liT0YbQs7kJ4wCLcB/s1600/17171388d72761df.jpg
http://www.surrenderat20.net/2017/05/516-pbe-update.html#more
they seem to be related to the mission assets.
Like Otarie53 said they are more related to the mission assets. https://1.bp.blogspot.com/-fXBGH7auE6k/WRtjanrrtQI/AAAAAAABDew/Mlgu310rXKAgfYr_1qlWDB33j8tvP_JaACLcB/s200/12.jpg https://3.bp.blogspot.com/-iqWhczAE1xs/WRtjam3Xw-I/AAAAAAABDes/08aGSw5jnPYq1tlJYRVnidC_OeVKea4HQCLcB/s1600/13.jpg
as those 2 image assets were added as well which are mission related assets and have similar looks to the new summoner icons.
So it might have something to do with Riven/Yasuo, but I'd expect them to actually release skins with said icons and the skins team confirmed there are no more skins in the coming patch, so I don't feel these are related.
finally
yeah, you're right.
Popular champions really do make skin money.
