I think it's because they are useful tools that a lot of webdevs see and can see themselves reasonably implementing by themselves. (Like todo lists & habit trackers)
Also, quite a lot of tutorials are to-do lists, habit trackers and note taking apps.
there's definitely a lot of similarity to foam - these are both markdown-based knowledge bases build on top of vscode and extensions. the major difference with dendron is its focus on hierarchical, lookup based retrieval of notes (https://www.dendron.so/#hierarchies)
wasn't that something roam and or foam tried to avoid, because a lot of notes don't fit into one specific parent?
rigid hierarchies can result in friction to getting thoughts in. but having no hierarchy can be problematic in getting notes back out. dendron tries to walk the line by letting you create links between any two arbitrary notes but also layering on top a flexible hierarchy that lets you prescribe a canonical organization of your notes