Very few are able to successfully transfer from Indycar to NASCAR, and win at both. Tony Stewart was one of the very few who have. 2 different worlds. NASCAR is all slide, slam, and bang.
Where as in Indycar the area around the car cannot touch. If wheel to wheel contact is made, an accident is most always the result. Kyle Larson found that out when he took out Stingray Robb in last years 500. ( I think it was last year). Robb was having what looked to be a good race up until then.
Danica learned this the hard way as well. She did much better in Indycar, managing at least one win. In NASCAR she was a total disaster. A one woman wrecking crew... But saved herself in the financial aspect, because she was at least marketable, being a good looking woman, and made a ton of money.
This in spite of wrecking equipment left and right, without much to show for it except a slew of 20+ place finishes. Perhaps KB could have pulled it off. But we'll never know, and that's the sad part.