Why Are Elderly Cleaners using Brooms while Foreign Workers Use Machines?

Dear TRS,

Have you ever wondered why we have elderly cleaners working with brooms while there are able bodied young foreign workers driving around on street cleaners?

These street cleaning machines are made to be very small and compact these days and look quite safe to operate.

These vehicles are equipped with additional functions to vacuum dirt while elderly Singaporeans are always seen manually sweeping using brooms? 

I know that there are differences in the areas covered and the type of dirt being cleaned but it still makes me wonder.

Are our elderly Singaporeans untrained workers? Can’t they be trained to use simple machines like this?