If businesses think their employees are so valuable that blocking them from working for a competitor is necessary... then how about just giving them incentives

If businesses think their employees are so valuable that blocking them from working for a competitor is necessary... then how about just giving them incentives to stay? I don't know, maybe a huge bonus, or above-average salary adjustments against the competitor, etc? Or fix the toxic work environment so that they'll actually want to stay? Otherwise too bad, the business created unfavorable conditions for their employees, so workers should have every right to leave and work for anyone else, including competitors. Either employees are that valuable or they're not, can't have your cake and eat it too, Mr. Big Boss.