It's designed to encourage people to save money into their pensions, to make up for decades of the government underfunding social security pensions. It seems really shitty to make that tax break conditional on job security.
How should a post tax annuity be calculated? The simplest annuities can probably be done (e.g. pay 100k and receive 6k a year til you die). But, if you paid tax on the full 6k that would mean that the 100k was being taxed again. However, tax none of it and that would see no tax on interest because it was being paid through an annuity. That's before one even starts thinking about spousal benefits or inflation linking.
(But yes also had 1-2 jobs that the match had a vesting period)
I wonder if it's more common outside of tech?