We live in the UK, in an "expensive" region (south-east). Our average expenditure, excluding mortgage payments, over the last 10 years has been, roughly, £25K p/a.
We're hardly living a bread and water lifestyle.
When we hit 67, the state pension alone will give us > £18k. You just need enough to bridge the gap.
The truth is - most probably don't need anything like what they think they need to retire early.
The system just wants them continually on the hamster wheel.