It is a no brainer that anyone who thinks he has a slim chance of winning, he must have a public face. A face that has been seen countless times, a name that people has heard of and past achievements that he can be proud of. Apart from TJS, who has not submitted his forms, the other 3 has them.
There are hundreds if not thousands of such men that qualifies, but none of them has any desire to want to contest. Amongst these are outstanding personalities, who achieve much, all without any connections with the PAP. One thing stands out however, they do not have a public face and they prefer not to have one. Even if one of these individuals were to contest, he will not win because he is a nobody as far as the public is concerned.
Therefore, to those who keeps harping on this issue, that they are tainted because they had past links with the PAP, is dumb. If Tony Tan had never gone into politics and remain in OCBC, he would not be where he is today, and the same goes for the rest too. TCB will remain a humble doctor working his practice. I cannot say much about TKL, but being the opportunist that he is, he had his eye on contesting long before the issue of the mini bonds. When that happened, he went forward and use that to promote himself as a savior of the people against a heartless government. The rest is history.