In fact, the difference in points remained the same - Inter also played their game in a draw. It's a pity that Napoli did not take advantage of the opportunity and did not reduce the gap to 1 point. Inter was clearly focused on the game with Bayern (and they managed to win at the Allianz Arena) so they lost points. In defense of Napoli, we can say that the opponent was serious, Bologna is playing well at the end of the season, maybe this is not the worst result - Inter still have several difficult games ahead, so Napoli will have a chance.
With seven more games to play the Italian Seria A title is still open for all the teams in top five. Napoli that has led the league for a long time suddenly slipped and have never returned back to the top spot. The game against Bologna was an ample opportunity for them to reduce the point deficit with Inter Milan to two. But they sadly settled for a draw. I am not too surprised that they were not able to take the maximum three points because Bologna has shown in these few weeks to be a team that is worthy of playing in Europe next season.