Did you catch the part where I mention that many arcade machines already come with rear wheels built in, just for this purpose ? Look at the bottom:
I did, keep reading.
So what I am talking about is replicating that functionality in a non-permanent, detachable way. If balance is not an issue with the built in rear ones, would it be an issue with front ones? If so, why?
For precisely this exact reason. The rear wheels are attached, fixed, in a permanent way. Tilting the cab back in that manner simply means the entire cab is handled as one inseparable piece. The same would hold true if you used a hand truck with a strap. The cab itself has a built in "hand truck". Barring an catastrophic failure of the wood or some other mechanical failure of the hand truck, this is a safe, tried and true method of moving, what is effectively, a large appliance.
What you're proposing is a very small "foot" to slip under the front of the cab, then to tilt or shift the center of gravity over this fulcrum. The potential for the device to slip out of position is too great. My dad had a junk yard and this is exactly the sort of thing I used to experiment with as a kid. I destroyed a lot of stuff playing with that crap.
For 80% of the cabs out there, how can you ensure the device will stay attached and fixed while you move the cabinet? By straps? Kitty corner from the corner you're attaching to is typically another corner. You would need another L bracket just to hold the straps secure. By the time you reach around the top to position the bracket and secure the straps, you're back at square one. Moving the cab out from the wall far enough to work on it.
Hand trucks have been around for
years. Take this one for instance:

Their designs haven't significantly changed a whole lot over the years.
Figure out why they're designed like that, then come up with a better (safer) mouse trap.