will the upcoming games run will on the current consoles?

Yes in fact they will for a little while Sony has recently stated that these next gen consoles

Will not be a huge leap like Xbox360 and ps3 was instead Xbox one and ps4 will mostly be about shaper picture the graphics will not

Be amazingly better

Some will, some wont. New consoles suggest better graphics and game engines. Even stuff like gravity and all will be better. So games will be made mostly for new consoles, but some games will be made with old engines, which would be playable on old and new.