Does Microsoft sponsor viruses?

Not literally, it just took decades for them to starts adding any kind of security to Windows.

At worst, the life expectancy [before malware infection] of a Windows installation without a firewall and antivirus to protect it got as low as four minutes, not all that long ago..

There were so many vulnerabilities and unpatched flaws that the self-spreading malware that randomly probes IP addresses could infect any unprotected system on just about the first try..

It has got better, but it is still abysmal when compared to Unix/Linux-based systems - much of the internet runs on those and generally the only reason they have virus scanners is to trap Windows malware being passed through.

Yes always have always will

2

Stupid question.

No. Do you have any evidence that they do?

No