lmao, just as adding multiple coats of clear coat doesn't make the BASE COAT paint harder, nor does applying multiple coats of ceramic. +/- 9H is all you get. And you are correct, it is likely harder than a typical water based clear coat. That said, other than its cleaning benefits it does very little to protect your paint from typical road hazards.
The only argument you have is cost. It actually costs ZERO to do nothing. In that you don't have any concern for protecting the ORIGINAL paint job on a vehicle, why would you bother doing anything??? It seems very unlikely that anyone spending 50k-80k+ on their vehicle is going to flinch over a 300-1000 on protecting it from certain damage. They'll make up more than that in resale.
Further, regarding cost, you seem to be pulling those numbers out of your butt as well. I just checked xpels site and retail on a front bumper hood and mirror kit is about 250-300.00. Most people could do that themselves or find a local shop to put something similar on for that or less. Big deal.
So to conclude, I AM seeing the price difference and I couldn't care less because they do NOT do the same thing. Saying they do either makes you a liar or extremely slow on the uptake. As soon as you can show me a ceramic paint sealant that can take rock chips, keys scratches and swirls like the following PPF for 100.00, I'm all in...... Till then, you're wasting your time and ours....
70mph rock test.
https://youtu.be/OKg9akQyZNY
Brass brush torture test
https://youtu.be/Q75LcIdtVBY
Key scratch test
https://youtu.be/S5FH7pJ9JNU