system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: We went from 2g to 3g to 4g LTE relatively quickly. What is 5g and why have consumers not seen it yet? What's taking so long?
gpt
We didn't switch that quickly in the past. 3G networks started rolling out in 2002 and 4G networks started rolling out in 2010. It may have seemed faster because there were "3.5g" bumps in the middle, like the rollout of HSPA+.

In the last year or so, a number of telecoms have started rolling out LTE-Advanced (a "4.5G" technology, or the first one to technically be 4G if you're using the ITU's definition of 4G). 

5G is still a work in progress. Electronics companies are currently testing some possibilities for the technology, but the industry hasn't settled on a standard for it yet.