Honestly, I think it's a natural decline like human body. As you get older (40s), you have to work twice as hard to maintain your fitness. You can buy better clothes, get nicer haircut, better diets etc., but you can't buy 4-5 hours in a gym every week.

Facebook is like all the companies I worked for. They all have a great core product, but they need to add features to maintain its prices, so they focus on the features with marketing values, while its core products pretty much stay the same.