Then yes, absolutely!
Even if you were driven by revenue opportunity, it can still be worth starting a SaaS in a niche with a clear leader as long as you can clearly beat them in a few ways (ie. undercutting price, better UI / UX, etc).
Can you turn it into a viable business? Depends on how hard you hustle.
That doesn't seem easy at all.
$100 a month is practically nothing on an American company's budget. To many of them, $1K a month and $100 a month mostly looks the same. They'll happily pay either amount, so long as the solution provided actually does what you say it does and it isn't a hassle.