Exactly, it's so strange that people hold cycling to this impossibly high standard that doesn't apply to any other form of transport. In my experience, separate paths from the roads even unlit do a much better job of encouraging people to cycle whereas experienced cyclists will put up with traffic in a way inexperienced ones won't.
One of the main issues with cycling is that there are very much several camps:
(1. Leisure cyclists. Going out for a ride on their Halfords BSO* with the kids, probably drove to the park to do so. Unlikely to use cycling as a mode of transport so probably not worth worrying about, and even if on the pavement likely to be going slowly so little danger.)
2. Dutch style utility cyclists. Typically ride something Dutch looking or perhaps one of Decathlon's excellent B.Twin hybrids which have a wider range of gears but otherwise are comfortable sit-up-and-beg machines. Would use an off road path where provided as long as it's not a sea of rocks. Might use the canal but equally might fear falling in. In London may well use a "Sadiq cycle". Dressed in normal clothes and quite possibly not wearing a helmet.
3. Fast utility/commuter cyclists. Typically ride a high priced road bike (£1K plus), ride a longer distance and at speed and wear Lycra and a helmet, and these days often carry a cycle cam. Prefer the road even if there is a path, and are typically extremely aggressive in their riding style, often arguing that it's the only way to be safe, but in reality these are often no more accommodative of other road users (including vulnerable ones like pedestrians) than white van man is. Almost always testosterone-filled males under about 50. This is the group that often, due to their typically aggressive cycling style, get the moniker "Lycra louts".
(4. Hobby/club cyclists. Typically ride expensive road bikes on country lanes. Confident in traffic, but unlikely to be found in cities other than on the most direct route out, though most drive to their chosen cycling area. Generally fast but not aggressive - more often than not helpful to other traffic, e.g. a peloton will often wave drivers past if they can see for certain it is clear to overtake. Not really relevant to most of this discussion.)
(5. Mountain bikers, but these mostly drive to the trails so aren't relevant at all).
2 and 3 are the main ones relevant in a city, and there is a massive conflict between the two. The former like dedicated provision like the Dutch approach or the MK Redways, and don't mind it being a bit slower as long as it's safe. They might be confident in traffic (as they may well also be in group 4 on a weekend with another bike) but they aren't typically aggressive, and so will rarely choose the road. The latter wish to ride at speed on the road and are more interested in an approach that keeps cyclists there but disadvantages other road users (including pedestrians) to their gain. Unfortunately it isn't easy, other than in a total new-build area, to provide well for both - a wider road is better for group 3, whereas a narrower road with a dedicated facility alongside is best for group 2, and if you want to add good quality urban pedestrian-oriented safety features like central reservations with one lane each way you may even have to ban group 2 from the road which they really don't like.
I am not quite sure how you square this circle, but my view would be that (2) should be prioritised in any decision in urban areas, as that has the most potential for taking cars off the road.
* Bike Shaped Object, a common insult for the very cheap "mountain bikes" sold by the likes of Halfords and supermarkets, typically priced well below £100, very heavy, poor brakes, cheap jumpy gears etc. These "bikes" do more for putting people off cycling than any traffic does, and most cycling advocates wish they'd go away as a result. Students and the likes often put up with them, but if Old Granny Wiggins gets one she'll be reaching for her bus pass.
).
What segregated cycle routes we do have are very badly thought out. 
