Depends on mood. With windows now stock antivirus engine is enough! On Linux never required. If you are not surfing porn and visiting few old sites and just keep an eye as well not required!
Oh okay! Would you mind running a really cool program I have here for you?
And if I have to run your bespoke program, I will use a sandbox or VM whether an antivirus is running or not.
I asked a friend who happened to have Visual Studio installed to build it for me from source. AV: No problemo!
Don't we have cpu's with a whole set of hardware features to limit what <insert executable here> can or can't do? Don't we have OSes with fine grained permissions, VM's, capabilities, etc, etc? Weren't these things figured out like, in the late 70's?
There is also the problem of everyone having different needs, so permission profiles must vary widely. OS builders cannot assume anything about the limits of their use.
Finally users can be the weak link. They may not understand the risks of what the screen is asking them when prompted.
No, we really don’t. We have OS’s with the tools to give us fine grained permissions, but at the end of the day on a desktop OS, any program you run can do any damn thing to any other damn thing owned by the same user. Look to phones for security boundaries that make sense in a post-1970s world, but not any shipping desktop OS.
Then what do I need a computer for? /s
But seriously, when I had my work laptop and therefore didn't have adblock enabled, I was very surprised at what kind of sites had very... let's say questional ads. There are a lot of tech sites like Baeldung that have very shady looking ads.