However...
The vulnerabilities in SS7 have been known publicly for at least 12 years (per Wikipedia). While I realize that it's going to take an absolutely enormous amount of time and effort to roll out protocol "enhancements" and "upgrades" across the biggest network in the world without completely breaking everything but the (apparent) lack of any progress whatsoever is what makes me start to question whether it's just negligence or if it is, in fact, intentional.
The cellular / mobile phone networks, though?
Personally, I'm 100% convinced the issues there (CMEA, A5/1, etc.) were intentional and "by design"... For those who don't know what I'm talking about, just look into NSA's "alleged" involvement with CMEA -- knowing what we do now, post-Snowden, about the NSA -- and let me know if you don't feel the same way!
Back when SxS and Crossbar were still around, SS7 was seen as the technology that was so secure it would stop all hacking of telcos forever.
Same level of hyperbole. Different eras.