Jay Z is the anomaly and falls well outside the standard deviation of skill. While I do think he may carry some blame for this unfortunate trend...I think the real figurehead of it is Lil Wayne.
He was the first person, in my recollection, who glorified 'not writing.' He was also well known for spending un-fathomable amounts of time in the studio. To be clear, I am not a fan of Lil Wayne. He's no where near my Top 10 DOA, and even though I lived through his hot streak, I never understood his legendary status. There are some joints that I really enjoyed (Carter 2, 3, and some of the mixtapes).
Regardless, he inspired an entire generation of rappers. He also glorified using substances. He codified; Live in the studio, don't write, and substance abuse. Not only codify, but glorify it. It was cool to do what Wayne did. Again, not a fan, but Wayne is also an anomaly. These other "rappers" that try to follow him, simply can't. It's all a copy of a copy. Replicated, simplified, and mirrored to the point where the actual "skill" has been removed.
To the point of technology being a crutch, I both agree and guilty of using it as such. I grew up taking piano lessons and playing in school and marching bands. At a point in my life I was a very fluent in reading sheet music. Fuck, before I got into DAWs and samplers, I actually wrote my music on charts - be it piano melodies or guitar tabs. There is something to be said about sitting at the piano with pad, pencil, and eraser. Playing, replaying, writing, erasing, re-writing, the music you hear in your head. You learn your instrument, you use your ears, and you work on getting it right.
Now, enter the world of DAWs and samplers. I'll openly admit that my skills have taken a big hit since. I can just click/right-click the wrong notes. Move them willy nilly across the grid. It's more hunting for an idea. The writing process isn't crystallizing ideas and putting them to paper - it's waving a pencil across the pad and hoping it writes out a sentence. The same can be said about my guitar skills. Things like time-stretch/flex time or just being able to chop and re-align means I don't have to "nail" the parts. I can play them in and just 'tidy' it up afterwards.