Linux disagrees with you. A process is a core thing to the OS, not just "another abstraction". The terminal is an extremely shallow/direct interface to the OS, in a way distinctly more clear & certain than most other abstractions.

There's no better way to see real truth in computing. The shell exposes the base truths of the OS abstraction directly: processes, environment variables, stdio, signals, pipes. This is the fundamental toolkit of computing, and what higher-level abstractions we see (from language's stdlibs, to things like Kafka or SQS queues) are better understood in terms of the base computing fundamentals. The base unix tools define a clear set of capabilities we should be familiar with, & to call them just another abstraction, to focus on our own local platforms, ignores the base root that all computing so far eminates from.

This abstraction-relativism you present is highly dangerous. Arguing we shouldn't care about anything because there are abstractions everywhere ignores a realer truth, that some abstractions have been around & underpin nearly all systems & likely will continue to do so. We're only barely starting to play around with alternative conceptions, in projects like Fuschia. But this is a rare, novel, & just-emerging break from our common frameworks of computing. One that would behoove people to gain some competency in.