Well, perhaps they're better than nothing. The real thing wasn't a solid globe, it was a wire cage with a solid top third, surrounding a rather fragile sensor on the top of the mast. Impossible to mold in styrene or resin, and not really feasible in photo etch either. Sometimes the mast wasn't mounted, and I've seen one mast without the cage covering the sensor, though that was probably a fluke. This is one reason I've tended to avoid the M60A3 altogether--it's pretty much impossible to depict this critical part accurately.
Perhaps someday we'll have a printed version, though it would be hideously fragile.