This isn't what the piece argues. It doesn't claim people need jobs to be happy, and the word "happy" doesn't appear in it. The argument is structural: when capital depends on labor, labor has political, economic, and democratic leverage. When that dependency ends, the leverage ends with it.

Whether people find meaning in work or outside of it is a separate question the piece doesn't take a position on, because it's not relevant to the point being made. The question isn't whether we can give people meaning without employment (I would argue that most of us find most of our meaning outside of work), but who has bargaining power in a system where human economic participation is unnecessary.