I'd suggest at least doing some research before trying to put down a potential "competitor"/alternative to your own tech. This whole exchange is a tad too unprofessional to me IMO.
<person>
<name>markdown is okay here</name>
<bio>markdown is okay here</bio>
</person>
If you write:
<person name="markdown difficult here" bio="markdown difficult here />
Also if you want to create a new component you have to jump to the Javascript world. And you have to learn CSS. Along with Markdown and the front matter (yml). Each with non trivial amount of learning curves.
FTD is being designed as a unified whole. All components of FTD are written in FTD. There is no boundary between "author" code and "components". A reasonable programmer can pick up FTD in an hr, check out the first video on https://ftd.dev. A non developer can pick it in a week, check out the other three videos.
Svelte etc are cool, but haven't you heard of huge number of backend developers who can't get into frontend? Current state of frontend is extremely complex. You can not tell me billions of people can learn Svelte thing when even backend developers are facing difficulties. To use mdsvex effectively you will have to write components. Which means the entire web pack, bundling etc etc. Do not pretend these are easy, anybody, even non programmers can do it.
FTD is being designed to be easy to teach. The audience of FTD is people at large, not developers (and yes they can learn some programming, Excel is used by 100s of millions). I do not believe you are saying Svelte is the super best and no such project as FTD must exist. I believe there is scope of improvement and we are working on it, help us improve.