Why do I care about XAML if I have such seemingly lofty software development goals?

Wanting to improve things for many people using software by providing better tools for developers may seem at odds with my focus on XAML. Afterall, XAML is a relatively small language only used for making native (mobile and desktop) apps by people building with .NET.
If I wanted to really make a big impact, why not look to do something online? or with AI?

Yes, more people use web-based technologies than use XAML.

Yes, AI has the potential to make a massive change.

However, many people are focused on these areas, and I don't want to get distracted by something new and uncertain.

I know XAML and its related technologies very well.
Very few other people are working to make working with it any better/easier.
It may not be a big niche, but it's overlooked by most, so I can (hopefully) make a big (relatively) difference with my efforts.

The people who use desktop and mobile apps deserve the best software, just as much as those using the web. 
The developers who build and maintain that software also deserve the best tools.

There's also a lot of such software already in existence. 

Software becomes old because it continues to be valuable to a business. If it wasn't, it would be scraped or replaced. That so much of this software is around highlights its value and importance.

Rewriting old software isn't always practical, but it still needs to be updated and maintained. Making that easier (faster and with fewer risks of unexpected consequences to changes) can be a big win.

For companies with a lot of existing software, being able to use the existing skills and knowledge in new software is very appealing. Building new apps faster and in ways to avoid future maintenance fears is another big win.

Secretly (I'll tell you because I like you), focusing on this area is fairly low risk.
I'm demonstrating an understanding of businesses and how programming languages are used within them. I also hope I'm showing an understanding of developer wants and needs and my ability to create sophisticated solutions to meet those challenges.

Even if all XAML development went away or I had an opportunity to work on something very different, I'm confident I'm building (and demonstrating) useful skills for the future.