Earlier quoted context omitted.
I get the point about unhappy employees sticking around just for their cliff to vest, but what about attracting a new breed of employees looking for short term employment?
That's already a risk in tech, because wages are so high but ramp-up times are pretty long. They get weeded out relatively quickly and usually run out of desirable employers, though. That's why employers are skeptical of employees with multiple short-duration stints or gaps on their resume.
This is simply increasing the risk of hiring short term employees in addition to existing risks including the high cost of ramp-up times.