This survey makes it possible to compare all different ideas and from that one can develop some new insights about philosophical thoughts, but inevitable these are not insights in the reality. They are acquainted with the science of philosophy but not with philosophy herself. Nowadays the general idea is that reality only can be discovered by scientific analyses. And such an analysis has to be in accordance with a lot of directions and criteria, once formulated by important leading groups of scientists. Acting in accordance with that directions is considered as a guaranty for reliability.
Every deviation is of the devil.
This means that new ideas and theories can hardly become any acknowledgment until new groups of leading scientists declare that indeed there is a necessity for adjusting the directions and criteria. Of course this leads to adjustment of several theories too. The philosophical truth seems to be variable. The truth of yesterday is an other than the truth of today. So the philosophers adjust their ideas, just like scientists.