One of my favorites!
All 3 books in the first uplift series work fine as stand-alone stories. But book 1 (Sundiver) does kinda read like a prequel to the rest of the series. The inciting incident of Startide Rising is what sets everything else in motion for all subsequent books, and Sundiver takes place before that. But it does have a bunch of world building that is helpful context for the other books (and is still a fun story).
I recommend you read Startide Rising first, then circle back to Sundiver if you are enjoying the world and the author's style.
Two things, mainly. They do a lot of the production steps in-house, as opposed to having a web of subcontractors (who have their own subcontractors)for each component. But the big thing is just efficiency of scale. Building and launching 100 rockets per year doesn't cost 100 times more than one launch per year.