I'm sorry to say that this is a highly ignorant reaction to the situation. Nixpkgs was nowhere the size it is now in terms of contributors and packages, the growth in the past six years was enormous.
The amount of monthly contributions has doubled in the last four years alone, from ~7k to ~14k commits per month. Why did I take six years as a reference? Because 2020 is the year nixpkgs really started to pick up traction, and the growth has been almost linear ever since.
Your argument only holds if I were to say "it grew to its current amount of monthly contributions in 2020 and then stayed constant, without growing any further."
I'm sorry to say that this is a highly ignorant reaction to the situation. Nixpkgs was nowhere the size it is now in terms of contributors and packages, the growth in the past six years was enormous.