There can be many reasons to leave work, one of which as you stated would be limited praise/recognition. Many times people also feel that they would be better off in a different division if there is stagnation within their own division. Moreover, many times companies go through ups and downs and during certain phases management may decide on restricting innovation and choosing to pursue bolstering their current products. I believe a lot of larger companies are in that phase currently. For example, Johnson and Johnson currently does not innovate products as much as in previous years, rather they look to buy startups that are already well advanced, and upgrade/diversify their portfolios in this way. Employees may want to be actively involved in creating products rather than supporting products that are out on market already and this can be a key reason they choose to find employment elsewhere.