Anytime a genre shrinks from popular favor, that genre's gameplay characteristics tend to cater towards the hardcore users. People that still play lots of shooters tend to like this style, therefore it's now all they make. Same thing happened with fighting games...they got really complicated with all the 'systems' and gauges and whatnot.
I don't mind, I still enjoy the likes of Shikigami no Shiro and it's peers.
I'm really looking forward to Gradius V though. Even if it has a touch of manic, it still looks freakin' beautiful.