So long as you’re working for a company, what other metric besides profit could there be? That’s a similar question. You can make small surface-level improvements here and there. But you’re not going to tackle the core problem until you tackle the profit motive.
The directives to increase metrics like time spent come from above, but the actual work is being done by tech workers on the ground. And they're doing this work because their performance is measured by whether or not they moved that metric and whether or not they implemented those features—even if they know they’re bad for users.
But there's no way they can push back on it. They can talk about it—in their company Slack, in their public forums, at their all-hands meetings. They can express a lot of malaise about it. But they can’t argue against the experiment succeeding, because you can’t argue against increased profits.
You could imagine different structures of the company that might not have this problem. You could imagine a world where these companies empower rank-and-file workers to make certain decisions themselves, and give users a voice in those decisions. Workers and users could together decide what metrics to optimize for, and what kind of technology they want to build.