To be fair though, in general shooters are harder to design and build than elevators. For elevators, you really only change the number and height of the stages, width, rigging, and motors. All of the intricate stuff stays pretty much constant between implementations and can be bought as a kit from a number of suppliers. Most teams could design an elevator in 2018 without prototyping even if only the seniors had any experience with elevator robots.
On the other hand, shooters have a thousand and one variables you need to account for to get everything dialed in properly, and they will vary widely from year to year. It generally takes multiple prototypes to find geometries that will work, even if all the students have experience designing a shooter. Shooters in 2012 vs 2013 vs 2014 vs 2016 vs 2017 were all very different; elevators in 2011 vs 2015 vs 2018 vs 2019 were pretty similar.