I agree. As long as you understand the basic concepts, it's only a matter of learning the syntax, which is really not as big of a deal as the person you replied to is making it out to be.
We can have a debate on unidirectional data flow vs 2-way binding, how each framework manages state changes, how opinionated each framework is... How mature and vibrant each developer community is... etc. These are all another discussion though. My question is why must we reinvent the wheel again and again.
So you want all of these to be a universal-template-language - (D)HTML ?
You are a programmer, you will need to learn new syntax a few times in your career.
If some of the "biggest" complaints are "oh no I have to learn how to write for-loops again" - I guess svelte is doing the important stuff right.
Wayyyy back in the day(ok not that long ago - 80/90's) when I was learning a new lang (Pascal,C, C++) I used to tell myself If I can get an working example of:
1) "user-input (readline,scanf etc)"
2) "printing input/output"
3) "calling functions/procedures"
4) "Do the loops + conditionals"
5) "file I/O"
6) "Memory schematics"
You basically mastered the "building blocks/mrk(min-req-knowledge)" of the new lang and like maths you only need now practice or a good project.
TL;DR If you are a professional-career-programmer, learning "new syntax (we used to call them keywords)" is a requirement.