I'll share the sources later, as they are a re from multiple places, , altbough read the privitisation v Gov control, as it does contains some very pertinent issues, esepcially considering the fact that deregulation and breaking of State monopolies was the first step to infrastruture investments, basically the large phone companies were broken up, sold to investors who were then given tax breaks, subsidies and sometimes Government backed loans. A very politically fraught process.
Re the first, there are 5 billion mobiles in the world today. 4/5 are outside "rich" countries. Rich countries just don't have the numbers and the critical mass needed. The large mobile sets makers will not have the monies and the incentive to develop sets at the rate that they did. (One of the reasons Apple has struggled recently has been its reluctance to enter markets outside its comfort zone, unlike Samsung and Huaweii who'll show up anyplace.). Seconldy, mobiles went from "rich boys toys" to "middle class accessories" to "universal" in stages. The first two had happened and were happening in rich countries respectivley. Middle and poorer countries had also seen the first stage happen. What is often forgotten is how quickly stage 3 occured, Bacially, in the late 1990's mobile were till the accessory of the affuluent, in most places. In the early 2000's everyone had them*.
Absent that, I doubt mobile phones would have become cheap enough to ensure universal adoption in rich countries, never mind world wide as happened in OTL, in essence like pagers. IIRC the estimates for maximum globla market was 500 million to 750 million connections and that was seen as being very optimistic.