"You can't get a gigabit on 4G," claimed a senior staffer at a very respected organization. He is one of their experts on 5G. All the engineers know that 5G NR can't produce more than a minor performance boost - 20%-50% at best - at less than millimeter wave frequencies, less than 10% of 5G,
Actually, Gig LTE has been one of the biggest stories in telecom since 2017. Verizon demonstrated 1.45 gigabits in 2018. (Below) Qualcomm is now shipping the X24 modem, which can do over 2 gigabits. (Only Sprint has enough spectrum for that speed in the U.S.) (Also below, along with a Google News search fo Gig LTE). T-Mobile CTO Neville Ray thinks 5G NR will add 20% to 50% to capacity, but that's at best a while off. Because CA/DSS and LEE don't work yet in 5G, realworld 4G is often faster than 5G today.
One of his bosses recently testified 5G would have 5 times the capacity. According to T-Mobile CTO Neville Ray and other engineers, 5G in low and mid-band can have 20-50% more capacity at some point in the future
4G since 2017 is shipping with advanced MIMO and 3 or 4 carrier aggregation (CA,) for "peak" speeds over a gigabit and real speeds over 100 megabits.