You are kind of contradicting yourself, from one post to the next....or maybe you don't understand that the "spendy" epoxy is just a higher grade sealer than an acrylic that you would have to reseal every so often and or wax to maintain.
Your concrete was finished beautifully, to maintain it one would either polish and burnish in a heavy duty polish guard (still needs maintaining in your environment) or grind, epoxy and polyurethane it. (choosing the correct formulation is key) Neither will hold up to molted metal unfortunately....haven't found anything that can.
Kudos to your concrete finisher...it's rare to see such excellent work
Sorry for any perceived contradiction, I guess I could have added that the floor will eventually need to be re-coated in time with a better product than I have now, but since I spent the last winter cutting and welding I went with a cheaper topcoat for the season.
I have used Epoxy on cement floors in rentals, and it looks killer, almost like a Berber carpet, I love it, but it is expensive.
My floor's red color added about $350 to the cost of the floor. Sure if I want to keep it super glossy or redo that cheap clear coat every few years it will take time and a little money, but it was hard to compare that costs to $7 a SF X 720 when I was building. If I was just parking in the garage the 5 gallons of sealer I have would last several applications over several seasons.
Once I get my projects done my floor will look kinda tired, ill give ya that, painting a few cars and getting overspray on the floor and spilling reducers & thinners will take a big toll on the look, but thats a problem for any floor I guess, even epoxy. Can epoxy be stained or dulled by those things?
Next fall I will undoubtedly need to clean and seal with a clear that will be more permanent, but even if I had done that when I built the garage I would still need to redo it to get that showroom shine back.