I just makes no sense to use a browser for password management, which you seem to be advocating for. Browsers have many functions. Password managers one have one function. Anything that tries to be an all-in-one will not be good in any individual aspect. I don't trust security suites for that reason, so why on earth would I trust Google or Mozilla to securely store my passwords? I wouldn't trust anyone where password security was an afterthought addon and not the foundation of the product.
The argument could be made for Keepass (or any Keepass derivative). I've used them. I like them. However, you cannot deny that syncing between devices in a pain with Keepass; you'd need to trust the plugin maker and the cloud storage provider where you're storing your database. Most likely you;'ll be syncing to and from GDrive, which means you're back to trusting Google. I don't. That makes no sense; why introduce more variables than needed? If your argument then is to say that Keepass should remain local-only and users shouldn't be syncing between, that's not really modern reality. People have multiple devices, all which could need access to passwords. Tablets, computers, phones; etc., are commonplace now. Phones especially are pretty much necessary. But not giving it access to passwords severely limits their functionality.
And of course, there's the creation and updating of passwords and forms. Can you honestly tell me that creating form data is as easy with local-only managers such as keepass as it is with something like Bitwarden? It is not. Again, I like Keepass. But this is one of its major weaknesses. It can be done via plugins, true. But it's not nearly as intuitive and east to use and cloud-based managers. The ability to quickly fill out forms with pre-determined data, such as name, address, phone number, email, etc., matters a great deal to most people. For that reason, online managers like Bitwarden or dashlane are superior to local-only.
If you are a user that has one system and only one device, than yes, a local-only keepass derived password manager may work for you. This of course assumes you don't use any of the features described above. But that's not reality of most modern users, who need access to their info securely stored on-the-go.