A pair of subs positioned farther apart than 1/4 wavelength of the crossover frequency will perform worse than a single subwoofer in the real world. The 3db benefit of 2 subs goes out of the window when there is massive lobing cancellation off center.And, as noted elsewhere, a pair of subs or 2 is better than just one.
The only way you can make >1/4 wavelength subwoofer spacing work is if you have simulation software and individual delay and level control down to the 0.1ms range, and even then it’s a trade off on output. I don’t think OP has DSP solutions nor the time or planning resources to do it correctly.
But yes, You are correct. A “small” mid/hi on a pole, solely responsible for producing their designated (hi-pass) frequencies from a high location for optimal crowd coverage, and a subwoofer(s), which are boundary loaded by the floor, playing cleanly and efficiently is far superior to trying to deploy full range speakers on poles. They will run out of amplification, introduce huge IMD on the woofers while attempting to play low bass notes and they do not get boundary loaded like floor stacked subs.
Not to mention having to lift 100lb boxes 6+ ft into the air.