I was an SS7 network engineer for 20 years ..
The problem will take much longer to fix than a few federal inquiries because SS7 was built with almost no security in mind.
e.g. in the 1970s, the only organizations that can talk on an SS7 network are other SS7 providers, namely large telcos and some businesses.
The cost of entry was very very high.
Diameter is better as most telcos use point to point tunnels between statically linked points, but its still largely unencrypted and such.
The problem becomes when SIP trunks and Diameter peering come into the picture. There's functionally no barrier to entry and telcos are obliged to interconnect on a non-preferential basis to prevent the fracturing of the telephone system. (e.g. if Verizon decided to not interconnect a competitors customers).