One reason there are not more unique light standards is they are special order and the city does not pay Manitoba Hydro to keep large amount of spares in storage. The poles get damaged from traffic accidents, snow clearing, etc.
It is just not the custom designs in the exchange / downtown that are being changed out.
Here where I live in East Kildonan, Manitoba Hydro has been doing a concrete base / steel pole refresh over the last few years. Some blocks are done as part of a street reconstruction project, and others like my block were done because of failure of the 60+ year old underground wiring.
I am sure that the same thing is also being done in other parts of Winnipeg.
Here is Manitoba Hydro's current standard offering of street light poles
https://www.hydro.mb.ca/docs/billing/street_light_catalog.pdf