Neodymium magnets helped to make them more powerful wrt size, and I suspect newer materials also made easier building small full range speakers where one would

Neodymium magnets helped to make them more powerful wrt size, and I suspect newer materials also made easier building small full range speakers where one would have needed at least separate woofer and tweeter, which wasn't convenient in cheap devices. The membranes of many small speakers from portable devices look like they're made of two concentric sections having different consistency and optimized for higher and lower frequencies, so that the same speaker can reproduce a much larger spectrum. That's probably far from being anything audiophile, still much much better than the quality of any similarly priced speaker from say the 80s.