IT gurus - WTH is Meltdown & Spectre?

[nyslowhand]

Lot of alarming news about how everyone's PC down to smartphones are susceptible to hacking due to microprocessor hardware issues that were made in past ~15yrs. Maybe I'm just too naive, but I see this as more an issue with firewalls, Bluetooth/WiFi security &/or AV/Malware programs not doing their job! All the news articles I've read keep pointing to the microprocessor as being the basic vulnerability. Unless your PC is always connected to the web, like Win10's default, or the same scenario with a smartphone being connected via WiFi, how can these above vulnerable hacks be exploited??

Hopefully, someone with better understanding of this issue can shed some light for a technology inept dinosaur like myself.

[silent death]

Sometimes you are better off to get a external firewall besides the one you have on your PC...