I just don’t think it’s true as a general rule: if we are talking about lower volumes, then yes. But for higher volumes, I don’t think it applies as a general rule. Are you going to be faster training 35 hours rather than 25? 12 as opposed to 20?
You will always be limited by your ability to recover and manage the rest of your life. But also as a matter of principle, I’d say “It most likely depends.”
In another thread @Jolyzara posted a link to an article that summarized how training for runners has evolved over time. One thing it explained was the pendulum swinging between doing more intervals and more low-and-slow work.