What happens after the website launches? Is that just the starting line?

A new site is a reset, not a result. Google has to recrawl it, the old URLs have to point at the right new ones, and the conversion tracking has to be rebuilt because the forms changed. Sites that lose traffic after a redesign almost always lost it in those three places, not in the design.

The three things that decide whether a launch holds

1. Redirect mapping done before launch. Every old URL mapped to its closest new one, in a sheet, approved, deployed on day one. Not discovered in Search Console in week six.
2. Tracking rebuilt and tested. New forms are new events. If nobody tests them, you'll have a quiet month that looks like a traffic problem and is actually a measurement problem.
3. A crawl on day one and day thirty. Launches generate orphan pages, broken internal links and canonicals pointing at staging. All cheap to fix if you look.

What ongoing actually means

Not a vague retainer. The five things that recur: schema audit, metadata audit, internal linking audit, site health check, crawl and indexing monitoring. That's the work. If someone can't name their recurring tasks, they don't have any.