Here's how I understand this and why I don't care for robots...
You mentioned that any machine could be a robot....
Look at it this way:
I have to do my laundry.
I buy a washing machine.
It makes life easier for ME....but no one lost their job because I bought a washing machine----
Robots, instead, are very expensive and they will not be built for only one person. They will be taking away a lot of work from humans..those persons will lose their jobs.
A machine is not a robot:
from WIRED MAGAZINE.
“I would say that a robot is a physically embodied artificially intelligent agent that can take actions that have effects on the physical world,” says roboticist Anca Dragan of UC Berkeley. According to that definition, a robot has to make decisions that in turn make it useful―that is, avoiding things like running itself into trees. So your dumb, cheapo RC quadcopter is no more a robot than an RC car. An autonomous drone, however, is a thinking agent that senses and interacts with its world. It’s a robot.
Intelligence, then, is a core component of what makes a robot a robot and not a wind-up toy. Kate Darling, a roboticist at the MIT Media Lab, agrees. “My definition of a robot, given that there is no very good universal definition, would probably be a physical machine that's usually programmable by a computer that can execute tasks autonomously or automatically by itself,” she says. “What a lot of people tend to follow is this sense, think, act paradigm." An RC drone can act, but only because you order it to. It can’t sense its environment or think about its next action. An autonomous drone, however, can do all three. It’s a physical embodiment of an artificial intelligence.
source: https://www.wired.com/story/what-is-a-robot/#