But I can answer some of it, and while cost/simplicity is some of it, it's mainly because it's what gets the least amount of hate mail.
On the cost side, almost nothing is translated by a single person, so for any names and concepts specific to the work, there is a database of how to translate it so all the transltors do it the same way. The more complex that database is, the more time the translators and editors have to spend looking things up, and the higher cost the translation is. Worse, these days most of it is translated by machine and a team of humans just correct the errors, so no one is actually looking at the entire work and thinking about characterization and plot structure. Some times the translation editors have no idea what the show is about; they are just emailed a couple thousand words of machine translation taken from the middle of the work, with no background explaination, and told to check for errors.
On the more historical side of things, whenever translators invented nicknames to try to match honorifics, they'd get tons of hatemail. Fans have made it very very 100% clear that they absolutly do not want that. (Because everyone has a different opinion of the emotional connotation of say, Kay instead of Kei-chan for a character named Keiko. No one's opinion of nicknames and when to use Ms. vs Miss vs Ma'am vs full name is ever correct because it is different in different areas of the Engish speaking word and even between different groups. People in NY use names differently than people in Texas, churchgoers tend to use them diferently thsn athiests, etc.)
Fans want the original Japanese honorifics. But the average non-fan viewer simply won't watch many shows that use the original honorifics. Taking out honorifics results in a very noticiable uptick in viewership...but also a LOT of complaints from the hardcore anime fans. So if a show was likely to be watched mainly by anime fans, they'd leave them in. If a show didn't have preexisting fans and they are hoping to catch the attention of the general public, they just use names even when it matches neither English usage nor the Japanese honorifics.
Now that so much is machine translated and anime is more mainstream, the default is just names, with all honorifics and nicknames removed. You only get honorifics if someone specifically decides to tell the software to use them, which pretty much means its a high end property so humans are actually involved, or someone on the localization team is a big fan. (Which isn't as common as you think because if you're a fan of a work, you are almost never happy with the financially-limited localization, so they either choose not to work on their favorites for their own mental health or burn out and leave the industry. (Not everyone though. Pleanty of people can do it just fine, and do! It's just, a lot of people assume that translators must be big fans of all the works they translate, and it's actually only a small percentage.)
Also, no one really sends hatemail for awkward and unnatural sounding translations. Everyone just shrugs it off. So using just the name in all situations is both cheaper and avoids pissing people off, even if it results in a lower quality work overall.