Along with phone makers, service providers are cheating ITU out of their mobile data system, and their specifications. It's a very broad topic that I can talk about for days really, (I've followed phones diligently for a decade and above).
The closest example I could give you is if (setting trademarks aside), HP, Dell, ASUS, etc. all got together and released a new kind of computer port and called it USB4, and then Best Buy came along and started marketing the first USB4 compatible PC's on the market on their shelves. Technically, without Intel's hand, and without the specifications Intel set for the research levels achieved before a working USB 4.0 system is on the market, this is just the name of USB bastardized to get mass appeal. Yes, USB4 might be faster than USB 3.0 by all means, but it is not what actual USB 4.0 technology is/is supposed to be. It's just a label.
You are correct that the G represents generation, but each generation is supposed to roll according to speed/range specifications that the international committee decides upon, and such speeds have not been achieved yet (I believe the 4G spec is 1Gbit/s, but the current "4G" phones can only hit a theoretical of 144mbit/s connections).
There was an unofficial 2.5G in the past, an official 3.5G, and this current "4G" generation is technically an unofficial 3.75G. Thought I'd include that so you can see that generations don't exactly go up in integers. Also, the time lapse between generations is unlimited. True 4G could be 2015, while true 5G could be 2050. It's not according to when new tech is out, it's according to when standards are met.
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