I apologize for bringing facts to a G1 v G2 fight, but a little research shows:
The typical 2017 is listed for $58k
The typical 2014 is listed for $40k
Typical = median = 50% percentile of all trucks nationally listed on Autotrader. (sort by price and look at prices on the middle page)
This is the asking price, so a 5% or 10% discount seems reasonable. In addition, most are dealer listings so you could probably get an even better deal from an individual. And of course, location matters when selling, so a truck in CA will command a higher price than one in Iowa.
When I bought my G2 in 2017, 2014s were all over $50k, so they lost around $10k over the last 2 years. And most G2's stickers were in the high $60's, so it looks like they also lost around $10k over those 2 years too. But on a percentage basis, it looks like G1 depreciated more over the last 2 years than the G2.
(Comparing used resale to new resale isn't exactly fair, but it is the best we can do. That said, it is even more impressive the G2 lost less on a percentage basis going from new to used versus the G1 going from used to used over the same period.)