The song dictates the bottom end. What is driving the song? Is it the bass line, the drums the gtr, the keys, the vocal? what? It depends on the song. If the bottom end needs a low bottom to the kick with a point on it so you hear the beater, the bass doesn't need to go lower.You fit the bass into the kick. If the bass is playing 16th notes, putting too much bottom will blurr it. Adding to much kick or low bottom end may take away from the punch and clarity of the notes. So the answer is, there is no correct answer to that question, because it's something that changes on every song and every style of music. If it was jazz, the kick might be only felt, the song might very well be driven by the hihat for example.
How should I anchor the bottom end of a song? That's more important to know. Same answer. My old friend and great mastering engineer, Greg Calbi, called me today. He says, "I loved two of your mixes but the third one had way too much bass on it, I just wanted to call you to ask what you had in mind because it doesn't fit the others and I don't usually have to dig into your mixes". I explained myself and said, "make it right, do what you suggested, take out some bottom and add some mids, it'll be right for the song".
What he was saying was, your bottom end is drawing focus away from the song, you've got too much, it needs to chill a little and by adding some midrange to the song, it'll put the focus back on the vocal. That's the way a mastering engineer should hear and that's why I love his work.