The reason many Canadians believe that the only way to receive TV is via a BDU is due to lack of local channels. For 40 years, London and KW only had one local channel each. In London proper, at that time, it was almost impossible to receive any stations except CFPL and CKCO. CKCO was pretty weak in London, as was CFPL in Kitchener. That situation pretty much created the CATV cable industry. If Canadian cities had been better served by local TV, it would have delayed the development of cable TV and slowed the inroads of US network TV into Canada.
Canadian broadcasters have pretty much reaped what yhey sowed. That is, Canadians with a taste for US TV channels and programming. The current situation, where networks like /A\ are still NTSC, while all US networks are all high definition ATSC, just carries on the old tradition of Canadian broadcasters under-serving Canadians. This drives Canadians to watching US stations on a BDU.
Cable was operating in London before CFPL came on the air. Canadians simply wanted more choice in television - the same reason that they subscribe to BDU service today. As soon as a BDU service becomes available there is a steady decline in OTA viewing. Historically, cable was the only BDU and service was only available in relatively populated areas. The availability of cable topped out the level of BDU penetration until direct Ku band satellite service became available. The level of BDU penetration climbed again as almost the whole country has access to BDU service.
The real issue for local broadcasting is competition for eyeballs with BDU services. Broadcast network viewing has declined steadily over the years because viewers want the programs on BDU specialty channels. Watching a BDU service rather than broadcast is the direct consequence of choice.
If this was the US, both London and KW would have it's own CTV, CBC, TVO and Global affiliates as well as /A\. Just look at the south side of Lake Erie. Their are major network affiliates in Buffalo, Erie, Cleveland, Toledo and Detroit, many of which overlap.
In the US, local stations have programming exclusivity in their own markets through any BDU service - telco, cable or satellite. While OTA households on the edge of markets can receive stations from adjacent markets, most of the viewers use BDUs or have minimal antenna systems (rabbit ears) to get local stations. In Canada, out of market stations are imported in bulk by BDUs from all over the country and the US. Market exclusivity is destroyed resulting in lost viewership and lower advertising revenue. The only way to change this situation is substituting or deleting every program shown locally by a Canadian broadcaster from any other channel. The Americans provide program exclusivity protection for one week before or after local airing of a show.