I don't think this is clear cut. React has been around for more than 6 years. According to the latest State of JS survey[1], 72% of respondents have used React before and would use it again. That number is 7% for Svelte.

Svelte has a lot of interest, but it also has a very long way to go against a popular, 6 year old project.

[1]: https://2019.stateofjs.com/front-end-frameworks/