More secure? Only maybe
"It can be more secure to use one or two identity providers run by top technology companies, rather than using separate logins for every internet service, since the likes of Google and Apple are likely to run more secure systems."
That is true, which is why it's so important not to reuse passwords. However, while your password is likely more secure when the big four are the only people who have it, here are some other things that can happen:
Privacy nightmare: Any time you want to log in to something, your provider knows where, when, and how. Including things they have nothing to do with. Do you trust them to have that information? If they ever do get hacked, all your information is neatly stored in one place.
Companies can take it down for you: If they feel like it, the authorization providers can cut off your account or the ability for places you use to use that sign in. In the former case, you lose the ability to log into anything. In the latter, just the specific place (that's this article). Either way, your access could be disabled by someone who isn't the place you're interacting with.
Single point of failure: If the service you're using has a technical issue, or your ISP or theirs has an issue, you could lose access to all your SSO abilities even though you don't have any problem accessing the thing you'd like to log into.
Openness to breach: If your account isn't well-protected, for instance because someone offered you the option to log in with another party but served you a spoofed page which you didn't catch, they could be able to log into other services as you. While all four of these companies offer multi-factor authentication and it's usually well-implemented, that doesn't mean that everyone has that turned on and configured securely. If they don't, this could be a lot like reusing a password.
Compare this with a password manager, and in each case the password manager will win. Use one.