All this means is that traffic is very low

That is not what increasing pool balances mean. Increasing balances mean that RC prices are decreasing (i.e. each user's ability to interact with the blockchain is increasing, across all SP levels). This can happen at any absolute usage level.

So basically your position is it's fine that someone needs to put hundreds of dollars in to have basic functionality?

I don't have a position either way in the abstract. It depends on the actual costs of some particular level of usage relative to price being charged for it. This can be attacked in different ways, such as making the blockchain implementation more efficient so it can support higher usage. Just cutting prices and inviting unconstrained usage (for example low-SP comment bots making hundreds or thousands of comments per day as was the case before) with no way to pay for it doesn't sound like a viable approach to me.

Surely you would agree that there must be some SP level where the account can't use all if its vote power, and generally speaking that "low SP" accounts must have limited usage, right? Maybe that is <5 SP, maybe it is <1 SP, or even <0.1 SP, or maybe it is <30 SP or higher. We can't just pull this number out of the air, real resources must exist to support it (including with a much larger user base with many more such accounts).

AFAIK, the RC system was designed on the basis of physical resource budgets (for example, that it is sustainable for the blockchain to grow at ____ MB per day, that ___ msec of CPU is allowable per block, etc.) and then allocating these resources between users such that they can't be exceeded in the aggregate. These are real resource limits upon which the survival of the system rests. Now it is possible there are bugs or miscalculations in the early estimates, and that is certainly being looked at. So we will see what adjustments make sense to make.