I think the USA is sort of the same, my experience is layperson so I don't know if this is typical or normal: the company itself pays a fee to the vendor to mai

I think the USA is sort of the same, my experience is layperson so I don't know if this is typical or normal: the company itself pays a fee to the vendor to maintain your 401k account under whatever the 401k legalities are (taxes being deferred etc.). A lot of time the funds available to choose from are the "institutional" kind that us mere mortals can't buy, only large vendors. So our money is pool-leveraged at scale using techniques and funds we individuals cannot access. When you leave that employer, you can leave your 401k at that vendor but after awhile the old company starts to bug you about moving it as it's costing them money to maintain an account for an ex-employee. I missed that subtle point you noted - most companies (? all?) only match contributions to their vendor 401k, so there's our internal-company incentive to get you onto their plan to get those sweet, sweet matching dollars.