If the ST performance of a CPU is overall about the same, and there are fewer cores than the competition, then I would have thought total MT performance will always be lower. But people are interested in Zen 4, because of it's apparent ability to compete with 2nd gen. Goldencove CPUs in most tasks, at a much higher base clock, using less power.
The problem with E-cores, is that they don't make up for the inherent high power usage of Goldencove's P-cores at higher frequencies (all they can do is contribute to total power usage, at a much reduced amount). The total number of high performance cores kept scaling up with the 9th and 10th Intel generations (I think many expected this scaling up to continue), but basically it has been difficult to scale beyond 8-10 cores, while bringing in the IPC advantages of microarchitectures like Goldencove on 10nm (Intel 7).
The main reason I'm considering Zen 4 over the 13th gen, is that AMD is offering the ability to switch to a DDR5 (offering higher bandwidths) platform, that they have confirmed is going to be used for many more years to come. I also tend to think that AMD's design on TSMC's 5nm process, scales better above 8 high performance cores. For example, I think the 7900X (12 Zen 4 cores) should offer more than enough performance (in heavily multithreaded tasks), for what most people need. To some extent, it gives a clue about where next gen Zen CPUs are headed - On the other hand Meteor Lake is still going to be using E-cores /hybrid core design.
Purely for gaming, it looks like either an 8 or 16 core V-cache CPU is likely to give the best performance per $$$. Particularly if offered at $500 for an 8 core model (likely considering the $449 MSRP of the Zen 3 based 5800X3D).
I can see why people want to stick with Intel though, if they already own a LGA1700 board. The 13th gen might actually be more appealing to some without the E-cores, especially if Intel charged £50 less across the board (not everyone is concerned with future upgradability, right now).