Linux is already used everywhere, from servers to satellites to phones to infrastructure. There's already a huge incentive to find exploits, moreso than Windows devices.

I do think more desktop-oriented exploits would be found if more people used Linux desktop, but I think that's more down to distro fragmentation and not every distro maker being as competent as others, or not having the manpower to keep up with development, as opposed to there intrinsically being danger in people seeing source code.

NSA would definitely want to keep some linux exploits around

And they'd be spotted in the source code and patched. If the code is proprietary, you can never trust that there aren't backdoors.

Linux is currently having parts of the kernel rewritten in memory safe languages like Rust, eliminating entire classes of exploits. Wayland is being developed with a far more secure architecture than the old X.org window manager. One important reason why they can do this is because the whole industry follows and stuff like drivers can be updated at the same time to keep everything working, and it doesn't even need to be the original developer patching it.

Microsoft's opacity makes it near impossible for them to do the same thing, so much of their security improvements are essentially hacked in on top of old code to not break compatibility. Instead of eliminating bug classes they rely on tons of techniques to make them harder to exploit instead - yet not impossible.

The point is, they already did. 99% of webservers run Linux. They are all out in the open and hackers love to get their hand on them as they are likely to have mailservers on them and they have a public IP so they can always be reached.

And most of them do not get hacked. And those that do mostly get hacked due to bad passwords or bad website code. I administer one and see the thousands of attacks running up against it daily (most are just attempts to log in with basic credentials). And of course I see the daily influx of updates from Linux.

If a new security flaw is seen, its often quite difficult to use. And with Linux somebody makes a patch before simple tool for hackers are out. With Microsoft products you wait till the next patch day, in the best case critical exploited bugs are patched in days. Also security flaws in closed source products are often easier to exploit and tools to use them are available fast. (Such flaws are often already discovered in open source products by third eyes and testers before they make it to production systems.)

Of course there are exceptions to the rule, like heartbleed. This was an easy to exploit flaw in an often used Linux service and it caused a big turmoil because many where to slow to patch their systems.

Also of course if Linux gets more popular on the desktop more software will be an attractive target for malicious actors and some software may get popular before many people take a look at the source code. But the situation will still be much better compared to closed source systems.

(Also of course more closed source software will be made for Linux then)

If that happeninux will also recieve more contributions and donations from that structers also linux devs also doesn't have to worry about building blobs, ads, tracking, making UI prettierso they can worry about real stuff and aolve those issues . The security of linux isn't because of the low amount of users its simply because it is what it is an OS build and used by nerds who whether you like it or not are some of the most tech savy people you can find and they have their heart in it because they are not doing it for corpos or salary . Also linux is the OS used by most (and best ) hackers and proggrammers and often recieve contributions from (only sometimes from the hackers but as the linux users are naturally paranoid they often review code and PR for vulnabilities instead of the need to add extra features cause jomo)

Also spelling, grammer etc.

Governments of Russia China India use Linux, nsa definitely keeping exploits active to keep tabs