Apple and Microsoft both have resources to dedicate as much man/machine-power as Google does for their browsers if they wanted to. They just don't want to play

Apple and Microsoft both have resources to dedicate as much man/machine-power as Google does for their browsers if they wanted to. They just don't want to play the neck-and-neck game any more. MS has opted to simply use Chromium while Apple as you say goes at its own pace. But they do have the capacity to match Google if they choose to, given some ramp-up time.