Like Dizzy Gillespie once said, "None of them blow easy". Yes, it's difficult to get good tone out of trumpets. Or violins, or guitars, or drums, or any other instrument. But assuming a skilled player, the tone of trumpet is more appealing to our ears than the tone of saxophones. It's ultimately easier to have nice trumpet tone than nice saxophone tone. Doves vs geese (or more correctly, elephants vs geese).

I've put in a couple of solid decades trying to improve my tone, and practice regularly to work on tonal issues. I appreciate the difficulty that any instrument represents.