Since the main failure mode of cv joints happens due torn or damaged boots allowing contaminants in an the grease out, would it be beneficial to periodically apply some type of Armourall type product to keep them less prone to cracking or tearing?

Yes.

I am a firm believer in applying a coating of vinyl protectant to the boots when the brake pads are changed or even when the tires are rotated. This also gives you the opportunity to inspect the boots for developing cracks.

It is a little harder to inspect the inner axle boots, but don't forget them. These boots typically last longer than the outer boots as they flex less, still, they will dry out.
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Keeping it running is better than buying new