Viruses are very much still a thing, unless the platform is Apple, or Linux. Android is in the middle; though based on Linux it’s had some incidents. The perception that there are no viruses may be because Defender is part of the operating system and it activates automatically if nothing else is protecting Windows.
ISPs are rather better at blocking malware than they used to be, so much crud never gets to us, especially compared with the past.
These days Microsoft Defender is competent whilst some previously famous names have degraded badly, either technically, or with unfriendly sales methods, rubbish add-ons, false positives, refusing to uninstall, or all of the above! Unfortunately it’s hard to find truly independent reviews because many security websites are biased promotions. One giveaway they’re biased is a long list of paid products with something nice to say about all of them and no mention of Defender or ClamWin!
I only use MS-Defender, but never use Windows for money or personal data. One reason is that Microsoft upgrades often undo my security lockdowns, creating loopholes, and it’s a pain having to put them back. Another is that Microsoft systems are enthusiastically targetted by criminals.
The need for anti-malware products is reduced by maintaining a high-level of internet hygiene. Avoid dodgy websites and freebie downloads! And take strong precautions if you enjoy walking on the wild side!
Running two anti-virus products at the same time wallops performance and stops legitimate stuff, so don’t do that.
Dave