"ESPN on ABC" is a bad idea. It's a branding nightmare and I'm sure the ABC affiliates aren't happy that their airwaves are being used to so directly promote a cable network that draws an increasingly large audience away from them.
Don't forget both ABC and ESPN are owned by Mickey Mouse so all the cash is going to the same place. But to tell your watching ESPN but not on cable ESPN, ABC will leave its logo up for viewers so we will know the difference. If no ABC logo you couldn't tell if you had ESPN on ABC or ESPN Cable on.
To the last post above mine, with all the name changes at ABC and all might a new logo be in the works to. I would like to see a new one the "round low case "abc" font could be different. Would anyone else like to see a logo change for ABC?