Your guess is as good as mine. That makes sense to me, but I can’t say for sure. Does anyone else know?

I think they can work from time to time, but they just don’t work well with most coordinates and styles.
From what I’ve noticed a lot of beginners make the same mistake with their parasols as they do with their coordinates, they’re cheap and poorly made which is the case with a lot of Battenburg lace parasols you’ll find online. When you do find a good one, they tend to only work well with things like Classic Lolita because they have a very period look to them, and even then it depends on the  coordinate. I have honestly never seen anyone who wasn’t wearing Classic Lolita look good with one.
They also aren’t good for a lot of types of weather. A lot of solid parasols come waterproofed so you can use them as umbrellas as well as parasols which you obviously couldn’t do with one that is completely made of lace. Lace parasols also don’t hold up very well with wind.

If you’re on a budget, why not make one yourself? They’re pretty easy to do and they’ll be cheaper than buying from a brand. It’ll also help you to get it more quickly and you know that it’ll be waterproof so it can be used as a parasol or umbrella.

They might just not have any this season. It’s also possible that they just don’t want to sell them online anymore because there have been a lot of reports of parasols (from several brands, not just Baby) being damaged during shipping.