We’ve had a lot of harmful and counterproductive gatekeeping surrounding the lanes=* tag over the years, and it’s creating some problems
I agree that it is quite unfortunate that lanes=* was created so car-centric (or dual-tracked-motor-vehicles-centered to be more politically correct) when it was created.
Having lanes=* exclude single tracked vehicle lanes breaks the plain-language use of what a lane is
Sure, but OSM tags and values are not (not have ever been) English sentences. highway=street_lamp or shop=hairdresser and tons of other tags are completely bonkers from English language standpoint. Street lamps are not types of highways, nor do we buy or sell people who specialize working with scissors on people heads. One should really learn to live with that.
We have changed the meaning of tags in the past in live use (highway=trunk comes to mind in the US); this isn’t a barrier to fixing the issue.
I don’t think that handwaving away serious blocker is a way to go, though.
Even today, USA has only about 232k highway=trunk roads. There is more than 15620k lanes=*. That is two orders of magnitude more. (e.g. all things being equal, if USA trunk situation was solved out in 1 year, it would require about 100 years to sort out lanes issue – and getting worldwide consensus is usually way harder then getting country-wide one).
Also note that lanes=* is far from the only tag that would need changing. turn:lanes, destination:lanes, change:lanes etc. as well as many dozens of related per-lanes attributes (e.g. maxspeed:lanes, width:lanes, bus:lanes:* etc.) would need to be redefined and retagged.
Namely excluding lanes for single-tracked vehicles.
Single-tracked vehicles are far from the only problem. See for example Pedestrian lane on the road about issue with on-road lanes dedicated to pedestrians. Also from the top of my head there is issue with shoulders (often used by 4-wheeled vehicles), difference between “hard/soft shoulders” and verges and what should count and what not too, as well as issue of parking lanes.
Also, interested parties may want to look at related discussion is in: Remove lanes quest · Issue #5317 · streetcomplete/StreetComplete · GitHub and Lanes quest should not ask for "car lanes" · Issue #5240 · streetcomplete/StreetComplete · GitHub
Can we agree that all lanes are lanes and tag accordingly going forward to make it easier on everyone involved?
As much as I’d love it, judging by my attempt at “pedestrian lanes” discussion above (with over hundred posts), which is just tiny part of this proposal, I’d guess the answer would be resounding “no” 
- even in that much simpler case, I was unable to reach a consensus, so best I was able to do was document multiple current ways of doing it. Things are always much more complicated then they look.
What might have a fighting chance however would be a well-defined and detailed proposal for alternative to lanes=*, as mentioned in this comment.