If your income is from selling your labor, you're working class. There are ways to subsegment the working class as positions become closer in alignment to the bourgeoisie (managers, e.g.), and it's valuable to distinguish them, but it doesn't change the fact of exploitation, who owns the means of production, who has control over the enterprise. The example of a manager is interesting because worker-owned enterprises still have them, still elect them. They don't serve the bourgeoisie to the same extent at all, but they are doing a job solely by selling their labor. The problem is that under capitalism, that subset of the working class becomes coopted into a means of control and squeezing other workers.

There's also the question of whether the contradictions from that exploitation reach someone who's getting a comparatively large chunk of cash, such as many tech workers. In other words, to what extent they have revolutionary potential. Imperialism also comes into play there, and other things. The latter raises good questions about the meaning of being working class in the imperial core, but it doesn't just apply to PMCs and so on, the spoils go to all classes to one degree or another: it would also apply to Starbucks workers, who must buy things to live like anyone else, including things made with child/slave labor, things artificially cheap.