The fact is you can reasonably run a modern Windows system without any antivirus at all. Normal user operations just browsing the web have never been safer.
But when you start having users unfamiliar with Windows quirks opening email attachments, getting redirected to sites because they don't have an adblocker, tricked into fake updates.

That's where antivirus saves your ass. It can monitor for failure and respond to it. It acts as a partial backstop to many other layers failing. That SHOULD be its job. If antivirus ever gets a legitimate detection, that is a huge series of failures to make it to your box.

It's easy to be edgy on this topic. Nuance appears pudgy.

Even in my hopefully measured response, people I respect can disagree based on their experience and value weights.

I could easily run my personal Windows boxes with no antivirus at all. I'd be fine. I know how this stuff happens, and my target profile for 0days.

I run antivirus anyway. That's my choice. It's informed by what I've seen. And my own mistakes along the way. I was a teen in the halcyon days of XP where you could artisan layer on numerable products to protect yourself.

Browser blast doors like Sandboxie, HIPS change alerting like Comodo, anti-exploit shims like EMET, and a plethora of antivirus vendors.

I don't know how to communicate this better without an extended speech presentation.

In my experience - the most important denominator of infection is not a product you buy, it is the behavior you act. Knowing what's not worth the risk. When you're being lead on to perform weird actions. Where you're desperate for solutions so you throw caution to the wind and even disable AV like when using pirated software.

That is the real difference and you cannot possibly spend enough money to ask your computer not to do what you tell it to.

I could impromptu give an hour+ presentation on how complex "What antivirus should I use" actually is.

The answer is Defender [for consumers, ATP whole other discussion not negative just way more points] is fine and stop downloading Office2013 activation crack torrents.

But it's also true some vendors have interesting approaches and if you like it, you can pay them. Everybody being on Defender is a single point of failure and attack. Monocultures are a terrible result.