New life for the shoot'em ups?

Noticed?
After years of complete absence in the last months more than a big name in the mobile games industry developed and published some new titles of that old but fascinating genre named shoot'em up.
Ok I'm 37, so I played the original version of Galaga and Space Invaders and I admit I can't resist the call of a good shoot'em up.
The question is: why now, after years of silence, more than a publisher revamped such a genre?
Evolution? Involution? Perhaps who presses the button (industry, not joypads...) is just like me 37 and wants to correct this error?
Anyway, wathever is the reason... thank you for this second chance!