I think this is right. Eloy Jiménez, Gleyber Torres and Jen-Ho Tseng were the 7/2/2013 class. The Cubs were penalized and couldn't sign anyone big in 2014. Then they did the same thing on 7/2/2015, signing guys like Miguel Amaya, Javier Assad, Christopher Morel and Isaac Paredes. This time, they were penalized for both the 2016 and 2017 classes.
Starting with 7/2/2017, the caps became hard and no team has gone past it since. No one succeeded in from the 7/2/18 or 7/2/19 classes, as Bertz pointed out.
The 7/2/2020 class was moved to 1/15/2021 due to Covid and that's when things started rebounding, as Bertz pointed out (Ballesteros/C. Hernández/Ramírez in 2021, Rojas in 2022, Cepeda in 2023, Cabada in 2025).