The welcome page is my single biggest gripe with Substack. Sending people to the /about or /archive pages directly doesn't help because the moment people click on the logo or title to visit the homepage, the email form is shown again. If Substack is marketing the platform as being designed for "Bloggers" too (https://substack.com/for-bloggers), then you shouldn't treat publications as merely being newsletters with an email form. You acknowledge it yourself in this HN post intro that Substack is much more than a newsletter! And I agree, except it doesn't feel like it.
The new Substack app allows people to read and discover Substacks without being shown the welcome form, it only makes sense to have the Web version behave the same too. While I would understand not changing it by default but why not at least have it as an option for writers? Substack already lets writers toggle a bunch of major and minor settings to tweak their publication, why not this too?