(I sincerely apologize, but without my phone, I really cannot take any photos)
In HDB Flats, with some without lifts, the stairs is a big challenge for most of the elderly. They would have to take their time, about 5 minutes to walk up or down one floor.
The stairs could then also become a safety hazard. Especially escalators. If the elderly would accidentally lose balance, they would tumble down the stairs. And with stairs it would not be easy to keep the balance of their body the same.