You are forked if your manager is ever compromised. It's only a matter of time until a major breach happens with a popular password manager.
You are forked if your machine is ever rooted too. Security isn't about perfection, it's about economics and threat models. For the average person the biggest fundamental risk comes from one of the vast numbers of services they use, none of which they have the slightest control over or knowledge of, getting breached, bought, leaked or whatever. As long as we need to use passwords (long past any technical reason for it, but legacy and inertia tends to make change extremely had) for authentication, it will in turn remain necessary for people to use passwords for every site that are good (random of sufficient length), unique, and can be changed at any given arbitrary time (in case of service compromise). It is simply not possible for most humans to handle all that in their heads, perfectly and indefinitely. Which in turn leads directly to password managers, end of story. It's not a matter of them being ideal or even desirable, they're necessary under current common authentication practices.
>It's only a matter of time until a major breach happens with a popular password manager.
Explain what you mean by this? Most password managers operate purely client side, and all actual password managers perform encryption client-side, there is nothing to "breach" to get general access to a wide swath. A persistent targeted threat is an entirely different scenario. Or did you mean you expect the password manager application software deployment system itself to get breached and thus release a malware infected update? That though isn't an issue limited to password managers at all, it's one that you can at least somewhat counteract yourself since it's ultimately on a system under your control (and there are OSS password managers, etc), and password manager devs have better domain knowledge and specialization then some random service.
In terms of threat model it's a no brainer. It's disappointing to see continued protestations against password manager usage on HN of all places, short of some theoretical discussion of switching everything to proper public key auth. Even a full court industry push starting tomorrow though wouldn't eliminate passwords for likely years if not decades, and in the mean time everyone has to make the best of it.