> Why are these social arguments missing from pre-2009 (when Uber was formed) literature?
Potentially because you only cited two studies when discussing a massive industry and are probably purposefully ignoring all of the work done to support the point you claim is ignored?
There are decades of research on the very points you claim are ignored. A small sample:
* Do Economists Reach a Conclusion on Taxi Deregulation (http://www.emmanuelcombe.org/moor.pdf)
> Because taxis are more expensive than other transit services, they must offer something that other transit modes do not. In particular, taxi services are important to certain segments of the population. Seniors, housewives, the disabled, and the poor each account for a much higher share of taxi trips than their share of the population (Rosenbloom 1985; Weiner 1982).
* Factors Affecting the Use of Taxicaps by Lower Income Groups (http://trid.trb.org/view.aspx?id=92135)
> Previous studies and our data suggest that the poor often choose taxis because they are the principal option when an automobile is not available. Taxis appear to be chosen over conventional transit (when it exists) because they offer greater service flexiblity, convenience, and duration of service, as well as better meeting the security demands of the poor. Increased availability of taxi service by reduced market entry restrictions and reduced cost of taxi service by permitting group riding and providing subsidies would increase the mobility of the poor.
* Subsidized Taxi Programs for Elderly and Handicapped Persons in the SFBay Area (http://trid.trb.org/view.aspx?id=70030)
> The objectives of the report are: (1) to describe six programs which deliver transportation service to elderly and handicapped persons utilizing the subsidized taxi mode; (2) to identify the essential similarities and differences among these programs; (3) to illustrate, in qualitative terms, the nature of the costs, efficiencies and impacts on taxi operators, subsidizers, and users of the six approaches; and (4) to interpret this information and identify those findings which appear to be transferable to planners in other localities. The subsidized taxi programs are successfully delivering transportation service to elderly and handicapped residents in all locations as evidenced by rising client enrollment and ridership volumes. Overall, response to the programs has been and continues to be extremely favorable.
* The determination of acccessible taxi requirements (https://dspace.lboro.ac.uk/dspace-jspui/handle/2134/2284)
> This report describes the results of a programme of ergonomic research undertaken to provide a scientific basis for the generation of regulations concerned with the introduction of accessible taxis in the UK.
* Modeling urban taxi services with multiple user classes and vehicle modes (http://front.cc.nctu.edu.tw/Richfiles/22015-Wong-Wong-Yang-W...)
> One of the main issues is the provision of several modes of taxi services in many large cities. For instance,
there has recently been a concern about the provision of easily accessible taxis for the handicapped, whose travel characteristics are very different from those of other customers.
* Compromise & constraint: Examining the nature of transport disability in the context of local travel (http://invent.newmobility.org/library/wt8-2.pdf#page=42)
> While major advances have been made over the last twenty years in the planning and provision of transport that is accessible to all, the links have not yet been effectively made between applied work on transport planning and the major developments in theoretical understandings of disability which have been taking place during a similar period. Existing studies have attempted to measure transport disability, but have generally failed to link it to wider theoretical or structural concerns, or to explore disabled people’s responses to transport disability.
* Taxi - Why Hailing a New Idea about Public Accommodation Laws May Be Easier Than Hailing a Taxi (http://heinonline.org/HOL/LandingPage?handle=hein.journals/v...)
> Municipal policies have also been developed to combat the problem, some demanding automatic confiscation of the cab if a complaint is alleged, others requiring cab drivers to take at least one fare a day to underserved neighborhoods or face suspension.