I am having the same thoughts. As lazy engineers, we try to optimize and automate everything. Heck, even food is optimized with things like Soylent, but for workout and muscle building there just isn't anything yet. There are so many things I want to do in my day, and putting an hour away to go to the gym and do a few reps here and there is time that I would really love to invest into something else.
I'm wondering if it's really that difficult to 'invent' something to make it easier. Recalling my school biology lessons, muscle build because of ripped muscle fibers that grow back together, just stronger. It sounds so simple to build something artificial that does this automatically to your muscle zones without working out.
On the other note, maybe it's good that we don't have that yet. A good physique, big arms and things like visible abs are a great trophy you get for investing hard work and time. Not everyone has it, which makes it so desirable.