Luckily, it's not Doomsday for WiFi yet. Clever KRACK notwithstanding, the attack isn't easy to pull off and requires proximity to the WiFi access point. Big companies like Microsoft and Apple have been notified and there are software fixes available to plug the KRACK menace, so please make sure you install any security updates that arrive.
Making sure that traffic you send and receive over WiFi is encrypted will also help protect against your data being taken or tampered with, although this again depends on if for instance the Transport Layer Security (TLS) protocol is set up right with up to date software.
There are some important lessons to learn from KRACK. First, industry standard specifications need to be reviewed regularly. Sometimes they're so complex that vendors creating products with them get it wrong, as is the case with the BlueBorne Bluetooth vulnerability that was also discovered recently.
Technical specifications can also be buggy, or contain flaws that nobody thought of at the time they were written. The researchers who discovered KRACK noted that other protocols could have the same sort of flaw, and they probably need to be rethought and updated as well.
Second, KRACK is a strong argument for using software defined networking (SDN). This is next-generation technology that New Zealand led the world in before a law change forced the test lab out of the country.
Without going into too much geeky detail, SDN makes it fast and easy to reconfigure and update network gear when these security alerts appear. That's exactly what you want, especially for companies and public-facing networks where updating each connection device is difficult, risky and takes a long time to do.
The United States National Security Agency (NSA) is a proponent of SDN which says it all.
In other words, we should anticipate that just about everything can and will go wrong at some point, and be ready to fix it.
That's an obvious thing to say. I'm still nevertheless betting that open, totally unprotected WiFi that's found everywhere despite all the warnings will remain a greater threat to users for the next few years than the KRACK hack attack.