yeah I've found that too :? SChwalbe City Jets go on/off with one lever at most, and some WTB tyres I have are the same. Both are wire bead. That's on Mavic 217's and XM117's.
I think it's a rim/tyre combination mostly, some are dead easy, others can send you to an early grave
My Conti Rubber Queens were awful to try and get on and off my Mavic ruins. By contrast the Highroller / Minion combo that replaced them popped on no worries, brand new steel bead. It's been worse when it's cold, then you hands really hurt...as does the language that follows!
I'm dreading my first puncture on the road bike...