5G is making great global progress compared to the early days of 4G LTE and 3G

5G rollouts are really not as bad as they seem
Commercially released in the final quarter of 2009, 4G LTE was only used by around 1,000 customers (yup, one thousand people) in Western Europe "initially", adding 20,000 users in North America in 2010 for a grand total of, believe it or not, 23,250 connections globally by the end of that year.

Things didn't improve very rapidly, as 4G LTE needed roughly two and a half years to jump to 17.9 million connections, which is pretty much where 5G is just a few quarters in. 3G adoption was even slower, not to mention 2G's long walk of 14 quarters from 0 to close to 18 million users in December 1995.
Obviously, this doesn't mean you should expect to see a billion people connected to 5G tomorrow, but the number could grow from 17.7 million to a robust 91 million by the end of 2020. Of those 91 million connections, North America is projected to account for 13.9 million, which would be a very solid improvement from a regional tally of only 587,000 in Q4 2019. You can call that the T-Mobile effect, seeing as how Verizon and AT&T's 5G rollouts remain primarily focused on small parts of large cities.
There's plenty of room for both 4G LTE and 5G growth for now
Until 5G becomes truly prevalent, which is unlikely to happen earlier than 2025 according to some industry pundits, 4G LTE will naturally continue to rule the usage charts, looking at a predicted jump from 5.3 to 5.9 billion global connections by the end of 2020, including 513 million (representing a 6.1 percent year-on-year growth) in North America alone.
Those numbers are driven by ubiquitous LTE-enabled phones, as well as a grand total of 993 LTE and LTE Advanced networks available worldwide on a large scale as of March 16, 2020, compared to only 59 5G networks, many of which still suffer greatly in terms of both coverage and speed.

But by the end of 2020, that latter figure could nearly quadruple to 200, while the coverage is expected to gradually improve over time and the number of compatible phones will surge rapidly, with prices set to dramatically drop.
All in all, the 5G revolution is actually ahead of schedule, according to 5G Americas, and should continue to ramp up a little faster than many analysts had initially forecasted, even though this expansion might feel slow for the general public.