Seems the situation has been reversed, it's about 1/3rd old, 2/3rds new now (maybe not that drastic, but there is a lot more Hayek-forward content than pre-Hayek).
Don't let me spoil it for you! My opinions/observations are my own (and I'm a grumpy git). There are quite a few watches there, but you could really feel the visual emphasis was on the newer/now, outside of the Moon watches. You may have a different impression than I. As
@kov has said, I am sure Covid has not helped...
I've been to MIH in La-Chaux-de-Fonds twice, it's rather good, goes back further in time (haha) than Patek Philippe's museum in Geneva (it has Egyptian water clocks, a ton of older clocks from buildings and concentrates more on the art/technique of older watches and clocks). Were I to rate the museums I've been to in Switzerland;
1. Patek Philippe Museum, Geneva
2. MIH in La-Chaux-de-Fonds
3. Espace Horloger in Le Sentier
4. Omega Museum in Bienne
I have yet to visit the other watch museums in Bienne, Le Locle, Zürich and Schaffhausen, so the list is incomplete.