Eight years into 5e and I still can't believe how misread this section is. First, it's not a rule (and therefore neither RAW or RAI), it's barely a guideline. Nowhere in the Adventuring Day section does it say that DMs should or must create an adventuring day in that way. It only provides a rough estimate of what an AVERAGE party with typical luck SHOULD be able to handle before NEEDING to take a long rest.
I am following RAW and RAI when I create a 1 encounter day, a 3 encounter day, or a 20 encounter day (though the party better try to find ways around some of those when I do if they expect to make it to their objective).