The way you phrase your question assumes that there's a constant ratio of dollars spent per the value of the night awarded. In some hotel programs it may be closer to constant but in most it's far from it.

For example, you mentioned Hyatt. You didn't specify which night of the week. And you didn't specify how often in which months you might stay at Hyatts.

If you only stay at a Hyatt once every 4 months, you don't qualify for any promotions, so you're probably right. But if you stay twice during the current Faster Free Nights promotion, you get a free night for every two paid ones. Except the free night must be a weekend night (and only redeemable for a few months). So if you need a weekend night, it's of much higher value than if you can't possibly use a weekend night, in which case it's of no value. By extension, if you can make great use of FFN, then that makes Hyatt by far the greatest earning ratio (but ONLY WHEN you're using FFN).

Then there's the fact that the availabilty of bonus offers differs by ORDERS OF MAGNITUDE between different programs. And the publicizing of those bonus programs differs a lot too. So, for example, if you are willing to spend enough time reading FlyerTalk to learn about Priority Club's simultaneous 8600..8604 promos where you can earn 55000 bonus point (not counting the platry regular points you earn for one-night stays) for 10 stays, which can be redeemed for 5 nights at many Holiday Inn Expresses, or 2 nights at better Holiday Inns, or I don't know how many nights at their even higher-end properties, AND you have been able to stay 10 nights at Priority Club properties during the current promo period (ending Aug 15), then who cares how much you regularly earn at Priority Club hotels (because reading deeper in Flyer Talk you'll see they keep running promos like this over and over).

But it also gets more complicated depending on whether you're also after miles (and with which airline[s]) or care not a single bit about that. Because at Holiday Inn or Express you earn paltry per-dollar-spent points or paltry per-dollar-spent miles with domestic airlines, but for example earn 500 miles per stay with BA among other international airlines, and in combination with the above points promo you can earn double miles in their "25000" promotion at the same time! So this is a super value if you need miles in such a program on top of getting free hotel nights, but not as great a value if you have no use for any of the mileage programs at which you earn the high per-stay rate.

Similarly, the Hitlon HHonors program gives you both miles and points for each stay (normally, not only during promos), while Starwood and Hyatt give you only one or the other, so again it's hard to compare without knowing your exact situation. (Priority Club is also only miles or only points OTHER THAN for the bonuses which you're likely to only find out about on FlyerTalk.)

Meanwhile, all the math you can do about ratios doesn't mean much if you can't figure out a way to factor award availability into the ratio, since award availability differs between the different programs quite a bit (but, again, not in a way that can be distilled into a single number that works for everyone, since some programs have better award availability in some locations than others, or on some days of the week than others, or in some of their brands than others, or in some regions or countries than others).