To think that people like Dre, Snoop, Biggie, Tupac, Eminem (even though I personally think he's trash), Kendrick, Post Malone, etc. don't have talent? Give me a break. It's as silly as saying guys like Plant, Ozzy, and Daltry don't have talent because they didn't play a guitar.
I wanted to come back to this after taking some time to think about a reasonable response. But I think it basically comes down to your age and environment influencing your opinions on this topic. Remember the primary argument several of us are making is not about success or relative popularity within their specific genre, but specifically the amount of musical ability and knowledge required to do what they do. Lets take a relatively pedestrian rock act from the 70s or 80s with only a couple top forty charting hits. Lets say Uriah Heap for rock and The Outfield for pop, both had maybe 2-4 charting hits total in the US at their peak. Not exactly prolific examples of the peak of their genres.
Now if I was inclined, even in the age before computers made it trivial and you actually had to have 4 track recorders and mixing studios, I would have no problem recreating anything that rap artists did. Most of them post Public Enemy and Beastie Boys don't even have fucking bands and just literally play samples of better acts music. Chant a bunch of rhymes about wakanda shit to a loop of some song that fits the rhythm of the poem. Fuck, William Shatner does it on his spoken word albums (and some if it, like Common People and Has Been is actually decent in a non ironic way).
I would have to be a lot more talented to recreate shit from the two pedestrian bands I cited. I could recreate the vocals and keyboards, but I am nowhere near a good enough guitarist to do the guitar or bass parts, let alone the drum lines (at least the Uriah Heap ones like in Easy Living). And I would still be putting way more effort to achieve it than pretty much any rapper does. And even the vocals where I am strongest would probably not sound as good, because it would be like a pop song with one singer multitracking. And these are middle of the road acts. Get to the level of guys like Rush, Elton John, Eagles, Men At Work, and on and on and its not even a contest. And in ten or twenty years people will still be listening to Uriah Heap and Outfield. Almost none of the rap music will be listened to (primarily because the fan base will have mostly shot each other by then LOL), outside of a handful of truly addictive riffs that (/drumroll) were mostly written by or outright performed by white guys (Sabotage comes to mind, but gotta give the Humpty Dance and some Biz Marquee shit the nod too).
Again, this is not a talk about performance stage presence or marketability. Guys like Flavor Flave, Eminem, and Tupac are/were amazing entertainers and very charismatic. But that mostly only matters to the kind of people who want to go to a show and watch guys chant about wakanda shit for two hours. What I am arguing is specifically musicianship and adherance to musical composition structure that has been refined over two millennia at this point. Most modern music lacks the skill barrier of entry these days, but the fall off really happened around 2010 roughly. And autotune did not help any, either. As recently as Weezer, managers had been making acts skill up a bit (Weezer's manager famously made them study barbershop music to learn how to harmonize better, hence the cover of My Evaline on the blue album). Most modern music IS shit, which is why Weird fucking Al's band can cover every genre lately with little to no effort.