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I think zigbee is more "resilient" because it piggybacks off all the other zigbee devices via mesh instead of each device talking to the central router.

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Zigbee is also far lower data rate than even first-gen WiFi, which makes it more resilient. Radio protocols are usually a compromise between 1) range 2) power efficiency 3) throughput 4) robustness. Zigbee prioritizes 2, achieves 1 through meshing, 4 through error correction and other stuff, and mostly writes off 3. Point being it's not just meshing doing the work here, it is overall designed differently from Wifi and tuned for the purpose in multiple ways.

Note that 802.11 (original) is specified with 50% error correction at MCS 1 aka 1 Mbit/second rate. That is, for 1000 bits transmitted, 500 were data, and 500 were error correction. (Plus all the error detection codes like CRC32 on top of that).

This is a good example of tradeoffs: slower and less throughput, but way more robustness.

Higher MCS levels of 802.11 cut down on error correction to 25% or 10%, achieving more throughput but less robustness.

I dunno how Zigbee does it, but I assume it has more error correction at slower (ie: more reliable) speeds than even WiFi MCS 1.

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