The younger players are inconsistent now, but they might improve and perform way more consistently in the future. Also, Pant might return too which would be a big boost.
Consistency will come with more experience. Look at the players. Yashasvi Jaiswal is just 22 years old. Shubman Gill is 24. Even Shreyas Iyer is still in his 20s. Rishabh Pant would be a good addition to the squad as well, and he is in his mid 20s. And then we have all the younger players who are still in bench, such as Sarfaraz Khan (26 years old) and Abhimanyu Easwaran (28 years). These players can only improve with time. Even the second string keepers, including Anuj Rawat, Jitesh Sharma and Dhruv Jurel are all in their early 20s.
India won because all these youngsters wanted to prove a point to the selectors. That made them out perform themselves which in turn helped India. Jaiswal has cemented his position in the test team after yesterday. Sarfaraz will be selected for the next test match and Jurel will again get an opportunity. Consistency is not a big issue with this team there are good days and bad days that every player has to face.