In Svelte 4, the let counter = 0 syntax is already reactive by default, a feature enabled by the compiler. This has been the status quo for Svelte prior to the rune change. The introduction of the $state(0) rune actually provides more hints about its reactivity than before, and restore the original meaning of let counter = 0 (in rune mode). While it's true that the compiler's "invasion" into JS/TS syntax has been a point of discussion, this invasion has been happening for a while, and the initial shock wave has been well-absorbed by the community.

Interestingly, the new changes could be seen as a retreat from that initial invasion, likely triggering a different response from the community. In fact, the resistance I've seen (and my own as well) has been in the opposite direction—it's hating this retreat, complaining Svelte becoming less "magical." and more close to regular joe Javascript.