There seems to be a lot of variability in what architects do and care about. In your last sentence, I feel like you could often replace architect with structural engineer and interior designer with architect in other situations and end up with the same outcome.
I'm not familiar with the courses and topics that are included in an architectural program and if they subsume that of an interior designer. If so, then you're probably right.
But, as far as I know, they're separate disciplines.
