When a mass employment offer is made to steal or destroy another business, it's usually something ridiculous. For developers it might be a million a year each, for example. It's not an amount intended to be paid perpetually so it can be larger than the defending business can be paying to retain.

It is not illegal to do general hiring at good rates and shop for employees at a particular company. That wouldn't have the same results as buying a company. Plus, you wouldn't own their creations; you'd have to rebuild or clean room steal it.