The way I look at it - the majority of value with blogs and static website is content. Hence the majority of change is of content.
For apps the majority of value is functionality and that's where a lot of changes happen.
The main problem of maintenance happens where there is the most change - in JSX programming (I.E. functionality) is a first class citizen and it lends it easier to change. With templates content is much more of a first-class citizen.
Of course this is all in the margins, you can write blogs/static sites well in react and applications well in template-based languages. The tradeoffs are just a bit skewed in favor of each, and it mostly manifests when you don't have time to be disciplined about changes.
Could you expand on this. You assert that "applications" are easier to maintain with JS, but blogs are not?
Are you defining "application" here as something with dynamic and interactive content?
Also, why is it easier to "make and maintain"? I'm not necessarily disagreeing, just curious as to why you believe this.