This is exacerbated because the alternative is not either-or - the most cost effective system is often dedicated hosting + the ability to spin up cloud instances to take the peaks.
Doing so lets you provision your dedicated servers to run at much higher utilization most of the time, and make pure cloud setups look far more expensive, and most people with setups like that end up needing the cloud instances very rarely.
That's not to say there aren't exceptions with genuinely massive peaks, but even then it doesn't take a huge base load before a hybrid system starts to have the potential to bring substantial savings.
It translates to about 7krps/day. Assuming it's all in one region at day time, it's 14krps/12hrs, or 42krps/4hrs. It's well within a couple high-powered servers even in the worst case
Let's say that, for a unit of computing work, ,the cloud price is N times of non-cloud. I'm being a bit vague here for generality; plus, when not on a cloud, the cost structure is different, but bear with me.
Ok. Now, your load varies by a factor of up to 133x. But unless your peak load is over N times your average, it is still cheaper for you to keep machines which support the peak load and have a bunch of idle time.
Extra benefits:
* Can do other computational work (e.g. experiments) during off hours without impacting system responsiveness.
* Can perhaps put some machines to sleep, or other power-saving measures, during off hours.
Extra detriments:
* You have to take care of more system and cluster administration work than on the cloud.
Above N, the cloud makes sense. Close to N - not sure. Well below N - doesn't seem to make sense.
You'll need to tell us that N is low enough.