Are they? A traditional RTS like Age of Empires 2 or a Starcraft requires quite a lot of accuracy in quick-selection and movement orders, it would drive me nuts to try and do that on a mobile screen with no mouse. I know MOBA-style games are popular on mobile, but there's only one unit to control there.

The only non-keyboard-and-mouse RTS I can think of is Tooth and Tail[0], designed to play nicely with controllers (in a similar way that that Halo Wars was back in 2009), and while I'm sure high-level play in those games was indeed very high-level, the whole experience nonetheless just doesn't work for me, it feels 'dumbed down' still.

[0] - https://store.steampowered.com/app/286000/Tooth_and_Tail/