whether in usa or canada, local governments treat the incumbent local phone company and cable tv company as a default essential utility, so if it's not a legally enshrined right, it would certainly be shocking and weird if they didn't build to new places
of course in places where the local phone company or cable tv company shares aerial utility pole based infrastructure with the local power company, they're very close buddies as well
In most of the USA the local telcos are obligated to extend service to new construction as part of government grants they've received in the past. The obligation is usually for something like ~10 years, but the grant cycle is shorter than that.
The recent "RDOF" mega-grant has one of these clauses (at the census block level):
"All support recipients must serve locations newly built after the revised location total but before the end of year eight upon reasonable request"
These mega-grant things happen every 6-8 years. The last was "CAP II", preceded by "CAP I", etc. The telcos are basically treated like municipalities when it comes to federal grantmaking. This is basically the system that was lobbied into place after AT&T was broken up; the FCC just took over AT&T's local-loop capital allocation.
of course in places where the local phone company or cable tv company shares aerial utility pole based infrastructure with the local power company, they're very close buddies as well