There's clearly merit to both sides, but personally I think a major underlying cause is that libraries are trusted. Obviously that doesn't match reality. We desperately need a permission system for libraries, it's far harder to sneak stuff in when doing so requires an "adds dangerous permission" change approval.
For C#, I think they achieved that.
You might want to elaborate on the "etc.", since HTML updates are glacial.
The PNG spec [7] has been updated several times in 1996, 1998, 1999, and 2025.
The XPath spec [8] has multiple versions: 1.0 (1999), 2.0 (2007), 3.0 (2014), and 3.1 (2017), with 4.0 in development.
The RDF spec [9] has multiple versions: 1.0 (2004), and 1.1 (2014). Plus the related specs and their associated versions.
The schema.org metadata standard [10] is under active development and is currently on version 30.
[1] https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/... (New)
[2] https://web.dev/baseline/2025 -- popover API, plain text content editable, etc.
[3] https://web.dev/baseline/2024 -- exclusive accordions, declarative shadow root DOM
[4] https://web.dev/baseline/2023 -- inert attribute, lazy loading iframes
[5] https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/... (Baseline 2023)
[6] https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/... (2020)
[7] https://en.wikipedia.org/wiki/PNG
[8] https://en.wikipedia.org/wiki/XPath
[9] https://en.wikipedia.org/wiki/Resource_Description_Framework
[10] https://schema.org/
Yes, they cannot include everything, but enough that you do not _need_ third party packages.
Django and Spring
So Python's clearly not "batteries included" enough to avoid this kind of risk.