Vue 2 had really bad support for static typing. It's improved in Vue 3 but still not as good as React. TSX is especially good.
But the main issue is the automatic reactivity. It's difficult to reason about and leads to spaghetti code. We also had occasional issues where people would put objects in properties that had some tenuous link to a database object or something, and Vue recursively infects the entire object with getters and setters to make the reactivity work. Sometimes we didn't even notice but it makes everything way slower.
I haven't tried Svelte so I'll take your word for it!
Also this was 3 years ago so I may have misremembered some details. No nitpicking!
But the main issue is the automatic reactivity. It's difficult to reason about and leads to spaghetti code. We also had occasional issues where people would put objects in properties that had some tenuous link to a database object or something, and Vue recursively infects the entire object with getters and setters to make the reactivity work. Sometimes we didn't even notice but it makes everything way slower.
I haven't tried Svelte so I'll take your word for it!
Also this was 3 years ago so I may have misremembered some details. No nitpicking!