Client isolation doesn’t help. That is just the access point not routing traffic between connected devices. The problem with WiFi is it is a radio signal. Everybody in range can receive 100% of all communication on that network. Just by being in range the attacker can do passive sniffing. No wiretap needed like with cabled networks.

WiFi is encryoed if it uses a password. So any public WiFi without a password can be sniffed by literally every device in range (no need to connect to the WiFi for sniffing). On public WiFi with a password, the radio signal is encrypted but everybody knows the encryption key. So everybody connected to the WiFi can still sniff the traffic of everybody else.

That encryption is only on the WiFi level, so encrypted radio signals, not on the actually traffic level (like TLS/HTTPS etc).

No, why would it? It will run code in the context of the current user which is absolutely enough to start a new process that will run in the background, download more code from a attacker server and allow remote access. The attacker will only have as much permissions as the user executing the code but that is enough to steal their files, run a keyloggers, steal their sessions for other websites etc.

They can try to escalate to the admin user, but when targeting private victims, all the data that is worth stealing is available to the user and does not require admin privs.

There are many breeds of cattle. Some which are on their own for most of the year. I am sure with some carefully selection (and maybe a few generations of crossbreeding) there could be viable breeds for reintroduction to most biomes which historically had wild cows