
The real questions employers should ask
There are two issues with employment:
1. Is the employer getting good value from their working employees, remote or in-office?
2. Is the employee getting good value from their employer?
#1 is what the employer should ask themselves, not what the employee does on their own time. If the employee has energy to put into family, a side gig, or creating a startup, as long as they do what their employer pays them for on time, that other stuff isn't the employer's business.
Suppose the employer is concerned about employee retention, which is the only aspect of employees meeting #1 above, that starting companies and leaving impacts the employer's business. In that case, there are plenty of mechanisms for addressing that, beginning with the employer recognizing #2 above is the other half of the employer-employee equation. This is why good employers have RSUs, career & education advancement programs, proper compensation, employee stock purchase plans, bonus programs, etc.
Bad management getting even worse isn't a solution to employee retention.