Look at my post above. I explained what Westmore was working with. Pierce, Ashton and Smith did most of their sci-fi/horror/fantasy work in films, which means a much less harried work experience. While Smith worked on horror TV later in life, he was a consultant. That's the easy work for an emeritus-status master.
Take a look at what Ashton did during a hurried production (Star Wars). Look at the cantina scene. Very few of those aliens are actually worthy of acting as "hero" units. They're onscreen for a second at most, and their prosthetics are almost certainly static. One of the aliens is just a werewolf mask. Westmore had to create aliens that would give villain monologues or interact with the protagonists in a meaningful way. This calls for either a flexible whole-face mask that moves naturally (we didn't see many of those) which takes a lot more time to do, or just a forehead prosthetic with maybe some embellishments.
Actors have to emote, and Westmore obviously knows this. As worker on a TV series, he'd get his orders in advance, as assigned by the production supervisor. He's got priorities, where he has to spend more time on the recurring or meant-to-recur aliens, such as the Borg, Ferengi, Cardassian, Jem'Hadar, Vorta, Vidiian, Kazon and so forth. Those guys all look better than the one-off aliens, like those people on the planet of Lilith from Cheers.
Take your favorites, ask them to create prosthetics for 26 weeks a year and see what they come up with.
Take a look at what Ashton did during a hurried production (Star Wars). Look at the cantina scene. Very few of those aliens are actually worthy of acting as "hero" units. They're onscreen for a second at most, and their prosthetics are almost certainly static. One of the aliens is just a werewolf mask. Westmore had to create aliens that would give villain monologues or interact with the protagonists in a meaningful way. This calls for either a flexible whole-face mask that moves naturally (we didn't see many of those) which takes a lot more time to do, or just a forehead prosthetic with maybe some embellishments.
Actors have to emote, and Westmore obviously knows this. As worker on a TV series, he'd get his orders in advance, as assigned by the production supervisor. He's got priorities, where he has to spend more time on the recurring or meant-to-recur aliens, such as the Borg, Ferengi, Cardassian, Jem'Hadar, Vorta, Vidiian, Kazon and so forth. Those guys all look better than the one-off aliens, like those people on the planet of Lilith from Cheers.
Take your favorites, ask them to create prosthetics for 26 weeks a year and see what they come up with.