Earlier quoted context omitted.
because when you're on $150K, and enjoy your work, you won't jump ship to work with a dinosaur like Yahoo just for a pay rise?
I must be missing something. So Joe works as an employee at Somethingly earning 150k and won't jump ship to Yahoo for a pay rise. But after Yahoo acquires Somethingly -- and likely shuts down its product -- Joe will choose to keep working at Yahoo because...? Given that Joe presumably didn't have a say in the acquisition, what are the (non-monetary) merits of post-acquisition Yahoo over pre-acquisition Yahoo?
Yahoo is betting that it wouldn't be able to induce someone to jump ship, but once they have jumped ship, their work environment is "good enough" to keep them. Well, most of them.
It's the same reason why magazines and online services bill by subscription (it's a lot of effort to get someone to subscribe, but much easier to keep them subscribing), and why ISVs bundle a lot of crapware with major platforms (users wouldn't knowingly install their products, but if they're already installed they won't bother to remove them), and why UX designers make the default settings whatever benefits the company most (most users never change the defaults).