If anything it has been the opposite problem, with modern congresses having been more than happy to delegate away their powers. You might have heard the recent tariff news for example.
Modern being what? The main tariff laws in question happened 50+ years ago. The republicans in congress have been going out of their way to not interfere, but that's significantly different from creating new delegations.
Since each person has one vote why would outliers matters? It doesn't seem that length of terms doesn't even help with leadership roles The Democrats minority leader is Hakeem Sekou Jeffries who was elected about 12 years ago and Mike Johnson has been in the house for 8~ years. There are R and D members who have been in the house longer.