It's not entirely fair for the author to draw conclusion on this particular topic, especially ones as provoking as "cost cutting".

Shopping trolleys are one of those topics where the more you look, the more you find: especially when it comes to the wheels.

For example despite the article mentioning rubber as being superior to PU - it's not always suitable, or even safe. Such as for malls which use ramp-style escalators which allow a shopping trolley to be moved between floors. These must employ PU wheels which have grooves that match the escalator. This lowers the shopping trolley sufficiently for a rubber-brake to press against the ramp, preventing the trolley from moving.

An example of the grooved PU wheel and rubber-brake can be seen here: https://www.industrial-casterwheels.com/china-escalator_trol...