I do think there's more class granularity than that, and it's important to understand how such distinctions can make it more or less difficult to organize and cooperate. E.g. the idea of a petit bourgeoisie is useful for understanding why small business owners, despite indeed needing to work for a living, are generally against unionization.

But the core of your point certainly stands. "Higher wage" vs "lower wage" does not make a big difference in terms of our fundamental interests, and the interests of workers are far more similar than people realize.

> and the interests of workers are far more similar than people realize.

You're confusing "experiences" with "interests." Worrying about paying your mortgage isn't an "interest" you have in common with someone else. It's an "experience." But people with similar experiences can and often do have conflicting interests.