Having a think back at a few of the AMD / Nvidia head to heads over the last half decade or so and it just feels that RDNA is one of the biggest jumps we have seen in a while. Now while we know that the GPU "cores" between the green and red team are different and not directly comparable it is interesting to see how RDNA seems to level it out from a core count / performance stand point.
Kepler vs Tahiti GTX 680 - 1536 Cores HD 7970 - 2048 Cores +33%
Kepler (2) vs Hawaii GTX 780 - 2304 R9 290X - 2816 +22%
Maxwell vs Fiji GTX 980 Ti - 2816 Cores R9 Fury X - 4096 Cores +46%
One interesting thing to consider is that it has similar clock speeds to the 2070 super. I don't think Navi has quite hit performance/core parity with Turing simply because the 2070 super generally outperforms the 5700XT. Clock speeds and memory bandwidth are relatively similar, so Turing's "IPC" if you will is still slightly ahead of Navi.
I expect Nvidia's 7nm GPU will be 100-200MHz faster in general than competing Navi GPUs, so AMD will still need to go wider to compete with Nvida. Then again, AMD will probably have RDNA 2.0 around that time, so AMD may have made some noteworthy gains in IPC, clock speeds, and power efficiency by then. Perhaps they will be on true parity (since they will be competing on similar nodes) or even slightly ahead of Nvidia in those fields.
"There are no solutions, there are only tradeoffs"
- Thomas Sowell