The laser turntables sound surprisingly bad because unlike a stylus a laser will not remove any foreign particles in the groove. Unless the record is perfectly clean, it's going to sound very noisy indeed.
The Laser turntable was a really bad idea, one that attempts to solve a problem that doesn't really exist in practice: record wear.
A stylus rides on the physical surface of the record. The information (audio) is on the physical height and x-position of the groove, not on the image of the groove. Thus the laser turntable also reads dirt and even damage that wouldn't be read if the stylus was used.
On a proper turntable with a proper (reasonable quality, not-worn) stylus, a vinyl record can be played in excess of 1000 times before noticing audio degradation, according to AES tests done in the '60s. Under an electron microscope it was reported that the vinyl surface appears to "flow" or "compress" under the action of the stylus.
78rpm "shellac" records are designed so the needle wears (!). For this, the osmium needles of the era should be discarded after two record sides. What happened in real life was that the needles weren't discarded, so they developed cutting edges that did damage the records.
I don't think I'd agree that the laser turn table was a bad idea necessarily though - I mean if the laser turntable worked as you'd want it to, it could be really nice, because you wouldn't need to have any moving parts potentially, or fewer moving parts (series of mirrors to position the laser or something). And fewer moving parts -> machine will last longer.
Normal turntable, moving parts:
1. turntable spindle
(2). Motor (sometimes integrated into the spindle assembly)
3. tonearm bearings
1. turntable spindle
2. motor
(3). tray loader
4. tangential tonearm positioning motor
5. laser servo mechanism for precise positioning
6. laser focusing servo