What even is retirement age and what practical impact would changing it have on society? People can retire or keep working at whatever age they want as long as they can afford to
This is the natural consequence of declining birth rates.. it's either that or immigration right now.
Encouraging people to have more children requires drastic changes in society which is difficult to implement.
In this case, I presume they're taxed on their continued employment and so they're still paying into the pension they're receiving benefits on? I don't see a problem if that's the case. They contributed to the pension with an agreed payment date and followed the process correctly. I can understand how you feel that it's unfair, but I really don't see a problem unless they stop paying into the pension or stop paying taxes on their continued employment.
Like others note, UBI is a fair solution. Let's have everyone, regardless of age, be able to have a baseline. Then allow extra income form those who enjoy, or value, additional work and income.