This is no surprise to those of us who have spent time in the networking industry. The root cause of this problem is that the core cellular technology has been completely de-valued in the eyes of customers.
If you look at the high tech industry from an economic POV, it is obvious that the benefits of all the investment at every layer of the protocol stack is accruing to the internet companies like Google, Amazon & Facebook. It takes years of planning, tremendous knowhow and massive investment to create a cellular standard, and creating wireless equipment is still extremely complex. You need to hire engineers with training in electrical engineering and communication theory. But since the end customer places no value to the technology (how much extra would you pay for a phone to use a cellular implementation that does not drop calls?), the companies that build such equipment have collapsed.
10 years ago, 3 of the top 5 telecomm companies in the world were based out of North America (Lucent, Nortel, Motorola). All these companies have been devastated, their carcasses consumed by European companies that themselves went under. So the telecomm arms of Alcatel, Lucent, Nokia & Siemens, Motorola are now (or will shortly be) one combined entity. Ericsson and Huawei, who enjoy extensive support from their respective governments, are #1 and #2 in the world. Ericcson equipment is still nominally decent, but Huawei's is absolutely terrible and 1/10th the price. But guess what... nobody cares.
10 years ago, telecomm equipment was supposed to provide 5 nines reliability. That means that the entire network had to stay up for all but 5 minutes a YEAR, and the downtime had to be scheduled. I have seen senior executives fired summarily due to their organizations failure to do their part to maintain these goals. It is relatively easy to make equipment that can make a few calls and then crash. Much more difficult to make stuff that stays up for years and keeps on ticking. All these experts who knew how to design such systems are mostly unemployed or working for insurance companies.
The demise of the traditional telecomms have been accompanied by the decline in health of core technology companies. Qualcomm, which used to be the Bell Labs of the 90s and 2000s, and who pioneered most of the 3G and 4G technologies that we take for granted these days is struggling and a shadow of its former self. They are facing brutal competition from MediaTek, the Huawei of the communication chip industry. MediaTek is Taiwanese knockoff who has pretty much stolen Qualcomm's IP, refuse to pay royalties and are protected by the Chinese government (a bizarre situation considering China's official political stance on Taiwan). Mediatek's chips are known in the industry to be at least 3 dB worse than Qualcomm's chips, and far less stable. If you have a non-Qualcomm chip in your phone, you are far more likely to experience call drops and overall airlink failures. (Disclaimer: I have never worked for Qualcomm and have no connection with the company, though I do own some Qualcomm stock. I have, however, spent years in the cellular networking industry). There was a time when no phone manufacturer would have even contemplated putting such an inferior chip into even their low end phones. Now, however, Mediatek's chips are available even in high-end products sold in western countries. They pretty much own the third world.
Most folks especially young people do not make voice calls these days. Data is far more tolerant to airlink errors, and web protocols are so overweight and clunky that the efficiencies provided by a more stable implementation are drowned out by the sheer bulk of HTTP. Furthermore, the customer has now been conditioned to experience a poor cellular experience when they use their apps.
The other major factor is the demise of the cellular industry is the ascent of Wifi. Most folks are on Wifi > 60% of their time anyway.