Kobayashi was left without a drive after Sauber signed Nico Hulkenberg and Esteban Gutierrez.
Kaltenborn admits that she was surprised Kobayashi could not find another berth in the sport.
"Yes, it was surprising. Kamui, when he came to us, came with no sponsors, nothing," she told the Official F1 website.
"But we were convinced of his talent and it was, for us, the right step. He showed some great performances with us: his podium in Suzuka was such an emotional affair - he moved that whole crowd in a way I have never seen before. He was a great team player - he did so much for the team spirit - so it is surprising when such a pleasant person like him cannot get any support from such a motorsport-loving nation like Japan."
"This again should be a sort of warning that we maybe need to change something. When you have a race in a country and you have a ‘local’ hero it helps Formula One to be successful there. But I have also to clarify that we never made any promises to Kamui for 2013."
Kaltenborn defended the notion of 'pay drivers' but agrees that something has to be done to ensure the top talents find their way in the sport.
"All these discussions about ‘pay drivers’ have lost ground a bit for me," she said.
"What we see is that many partners or sponsors support drivers from the very beginning. A good example is Sergio [Perez]. He has been part of the Escuderia Telmex, which is a racing school. They have been supporting him from the very beginning and it is natural that when he enters the pinnacle of motorsports, they come along. You have so many top drivers out there who have also brought along their partners who have supported them right from the beginning."
"You don’t talk about pay drivers in lower series because it is normal that a driver has partners that support him. So why not use the same standard in Formula One? Then you wouldn’t have all these pay driver discussions. Sure, it would be good for Formula One to look more closely at the costs. We have to do something. Over the years we see that the economic climate is also getting to us. And not just to the smaller teams, but the whole sport. In this environment we cannot expect to always have a high level of income from the commercial rights holder. We really have to find a way to react to this."
Kaltenborn does admit it is a concern if experienced driver are leaving the sport solely down to a lack of financial backing.
"It is, in a way, worrying if that really is the reason they had to move out. That would not be a good development because Formula One needs to have the best drivers and not necessarily the ones with the money."
"But then one also has to be fair to the young drivers coming in and not immediately label them as pay drivers. There has always been fluctuation on the grid and nobody was harping on about pay drivers. Everybody who comes into Formula One is on a high level and if there are only a limited number of seats, then of course every team is looking for the best option. Who wouldn’t?"