Dependancies introduce unnecessary LOC and features which are, more and more, just written by LLMs themselves. It is easier to just write the necessary functionality directly. Whether that is more maintainable or not is a bit YMMV at this stage, but I would wager it is improving.
I don't think it really affects the point discussed above for now, because we were discussing average users, and by definition, the first person to code a plausible web browser with an agent isn't an average user - unless of course that can be reliably replicated with any average user.
But on that note, the takeaways on the post you linked are relevant, because the author bucked a few trends to do this, and concluded among other things that "The human who drives the agent might matter more than how the agents work and are set up, the judge is still out on this one."
This will obviously change, but the areas that LLMs need to improve on here are ones they're notoriously weak on, so it could take a while.