I've started looking into password managers these days and have come to trust the general concept. They provide convenience and very good general security if used right.
However there is one point of concern that remains:
What happens if my password manager service fails i.e. both the servers and the client (or browser plugin) are suddeny disfunctional. The password plugin cannot be used anymore. I cannot access my passwords via the web interface of the manager service. The built-in export functions of the manager is not available (client corrupted). Let's imagine e.g. a hacker attack that compromised both server and client side functionality. One could also imagine that a corrupt gouvernment obliges a password manager to shut down their service. As a security oriented user I have of course used randomized strong passwords everywhere and only personally know my master password. In this scenario I have now lost access to all my credentials. How could I recover my login data to all the hundreds of websites that is stored in the vault? Of course, we would hope that the service I use would recover "quickly" but then, I might still need urgent acces to some elements in the vault.
To me what would be needed is an external program that is capable of decrypting the locally stored vault, when provided with the master password. Since the encryption algorithm used by a service is usually known, this should theoretically be possible.
Thank you all in advance for your insights.
Some edits in response to the discussion: Edit 1: I have settled for the popular solution LastPass. If you have concrete answers concerning LastPass they are of course welcome, but I intentionally formulated the question non-specific, because I couldn't find much on this topic and it seemed really a "general problem" to me.
Edit 2: Manual vault exports + manual encryption. This is exactly the workaround that I use now: All in all the concern I formulated was not strong enough to discourage me from switching to tool - based password management, especially with this rather viable workaround available. Of course it would still be nice if a manager did this automatically.
Edit 3: Backup a working client version - LastPass is not ideal with respect to this issue, since there is no standalone app (or I was to stupid to find it). That makes it already more complicated to always have a backup of a working client version on my pc, because it is all browser plugin based. Otherwise this is a viable solution as well. - actually it is preferable because I would always be able to access the latest version of my vault. Edit 3.1 - so actually I was to stupid to find it - or rather the LastPass website is not very clear about it. The installer that is described as follows: "LastPass Universal Windows Installer
The Universal Windows installer installs browser extensions for Internet Explorer, Edge, Chrome, Firefox, and Opera." also contains a native app.
Edit 4 : Password recovery without access to the vault - Yes and no. First of all it is tedious. Secondly it doesn't work if the credentials for my recovery mail are also stored in the vault.