What's the difference between 18 and 27?

Now, I know what you're thinking... 9. On the surface, that technically is correct. But those of you who are astute will say "0" is the correct answer. Let me add a little more context to the question. When you're thrown in to the deep end and you're floundering, does it really matter if the pool is 18 ft deep or 27 feet deep? Nope, you're either going to sink or swim.

I raised this classic tenure-track-sink-or-swim question in this frame during a recent round table discussion with the other new engineering profs and some senior/established profs. Because I really feel like it's either sink or swim and that's it. That's not to say I think SnowU is the type of institution that hires 5 junior faculty and will ultimately fight it out for one tenured position. I think that's a ridiculous way to run an academic institution. But rather, I get the general feeling that either a person has it or doesn't have it, and it's not going to be something the institution does that determines that.

Needless to say, this definitely got some strange and awkward looks from the other newbies. Aside from being shocked that I had a more cutthroat view of academia, the common comments from both the newbies and round table leaders was that they didn't think it was a good thing to jump into the deep end. That, using the same analogy, I should find the stairs and take a more measured path towards the deep end, but ensure my head stays above water.

While I think I was/am prepared for the position, I feel I am continuously tested/challenged by the amount of work, scope of the work, and depth of the work. On the sink-or-swim scale, I'd say I'm treading water, but definitely waaaay in the deep end, which has the potential to be good but also the potential for a spectacular failure.

But if this approach is successful, (and for those of you who have done this) do you think it will have better lasting effects than if I just waded into the pool and learned how to swim that way? For example, I see it similar to higher salary effect for starting a new job. That is to say, if I can swim in 18 ft or 27 ft, then when I'm established, handling the even higher workload with being a tenured faculty member will be easier.

For those of you who have passed the tenure hurdle, how crazy is this approach? Is my assumption correct that handling more in the beginning will mean I can handle even more later? If you're just starting out like me, what has your approach been? Is it similar to this or different?