> Financial incentives — including stock options, restricted stock and pensions — are other ways that companies have tried to tie employees to their firms.

I've found vesting periods to be prohibitive enough that I don't even consider these things when negotiating employment.

Also, I'd add that job-hopping (what I'd define as working somewhere less than 12-24 months) seems to have been de-stigmatized – at least in larger tech hubs.