The quality in Vienna differs a lot by district. In some areas you can go for several km without any intersection with cars. In other areas you get what you describe.

If you stick to the river promenades, you have to share the path with pedestrians, but in most cases this is still better than going on the streets. Especially since it's not so noisy.

According to the official Website of Vienna, it's 1661 km. However, as mentioned here, this is what is included:

• 169.2 km of actual bike paths
• 170 km of mixes pedestrian/bike paths
• 44,6 km of bike lanes
• 142 km of multi-use lanes (like bike lanes, but less illegal for cars to drive on them...)
• 28.7 km of bike crossings and intersections
• 7.4 km of bicycle streets (where cars are allowed, but sometimes modal filters discourage driving cars there)
• 324.8 km of one way streets with a bike lane in the other direction
• 18.6 km of bus lanes that allow bikes there (and usually taxis, so it's pretty worthless)
• 275 km of bike routes (can be anything, but since these are not included in the other categories, it's simply quieter streets that cyclists are directed to using direction signs. Some of these actually do have a lot of traffic and are awful to cycle in)
• 8.9 km of pedestrian zones that allow cycling (but usually only "walking speed" which is not properly defined)
• 38.1 km of Wohnstraßen (google it, you are allowed to play football on the street, no through traffic for cars allowed, in reality those are parking lots)
• 358.8 km traffic calmed areas (honestly, no idea what that is. It probably contains "Begegnungszonen", which is a 20 km/h shared space, but we do not have 358.8 km of those)
• 73.9 km Mountainbike trails (mostly in the forest, you can see those in OP's map along the western edge

All in all, it could be worse, but we do not have 1600 km of actual bike infrastructure.