The issue is more the fact that west of Livingston the 276 doesn't serve anywhere of particularly high population other than Blackburn which already has the four buses per hour linking it to Bathgate and The Pyramids, all other settlements along the route are small villages. I agree They would've been much better rerouting the 280 or 281 via The Pyramids. It's kind of in the same position as the EX2 was where theoretically if you look at a network map it looks like a good idea, but when you consider supply vs demand it doesn't add up. There's been many routes covering the Loganlea - Blackburn - Bathgate corridor over the years and they've never lasted long, i highly doubt the vaccination centre which most people are only going to visit three times at most in a spread out period will make much difference to that.
I would be inclined to agree. My point was more that i was surprised they were extending the 276 rather than reinstating (or partially reinstating) the Broxburn - Edinburgh Park section of the 275. Regarding the X38 i'll reply in the FSE thread as that discussion is likely off topic here. Although what i would say as you bring up Winchburgh is that housing development doesn't nesserally equal thriving bus use, the issues many new areas face when it comes to public transport is that they're bought by younger people who are starting families and already drive cars, the age demographic tends to be fairly homogeneous so there's very few over 65s or under 25s, i mention this as they tend to be the main bus users. It really takes at least 10-20 years before the age range spreads out and bus use increases as those kids becomes more independent teenagers and some residents reach retirement age. That's not to say there won't be bus use, but the point is it's likely not going to be as high as you'd expect for the size of population.
There's also the 34A to Lanark which runs hourly most of the day so that's up to 7 buses per hour, pre-covid it would've been even more