I feel like they’re severely falling behind with coverage and speed. For example I live in a big city (London, Ontario) and I get 1 bar at my house and around even outside. I did a speed test with Fido and getting 5Mbps down. With Koodo/Telus I’d be around 130 Mbps. This was through speedtest.net. I used an iPhone 7plus
There are many things which can affect LTE speed -- strength of signal, network congestion, LTE band(s) or frequency(-ies) to which your device is connected, etc. The fact that you only get 1 bar of signal at your location could, in part, be a reason you're getting the speeds you note. The mobile providers have their cellular towers strategically placed. Unfortunately, their locations might not suit every customer. You can get an idea of your surrounding cellular towers here.
In addition, you likely noted those faster speeds with Koodo/Telus because your phone would have been connected to LTE-Advanced (LTE-A or LTE+). That is, your phone would have aggregated bandwidth from multiple bands to achieve those speeds. Note, I do not believe iPhones denote the advanced icon in their notification bar (see here). While Fido/Rogers does also provide carrier aggregation at some locations, they currently have fewer bands available to aggregate (see here). Fido/Rogers have now officially provided a timeline for the GSM sunset (see here). They won't be able to re-farm those frequencies until after the decommission date.
As noted, Fido/Rogers does offer carrier aggregation in some areas. However, it would depend on your location relative to the cellular towers. The different bands/frequencies have varying characteristics. For example, the lower frequencies can travel farther and penetrate better than higher frequencies (see graphic here). In addition, the different frequencies vary in their available bandwidth (see table here). It's possible that your location does not receive sufficient signal from multiple bands to allow for aggregation.
Hope this helps