Well if they don't they then have to spend lots of money and resources recruiting and training new people to replace those who leave because the services do not or will not meet their needs.
As discussed in other threads - the Australian submarine force was/is an example - drive people too hard, upset their sea shore ratio, don't understand their family needs and pay the consequence of not having enough qualified people to do the job.
The answer is not easy - if it was there would not be an issue.

