Gingko and plant evolution

The plant world is astounding. It turns out that flowering plants, angiosperms, are only at their peak in this geologic epoch. Relatively recent. Why should it be that this evolutionary mechanism (pollen and ovary reproductive structures) are the most prevelant? Is it a coincidence that Gingko biloba, when taken daily, can help with memory, while this plant is among the OLDEST living vascular plant relatives? Does it have some collective memory properties because its just been around for so long? And my book (Polunin's Plant Geography) says that plants just came up on to land at some point. Coincidence? Maybe over milennia, coincidence just morphs into evolution. Angiosperms have this complex method of reproduction, whereby the pollen grain has to find the flower of the appropriate plant (might be on another individual, far away from the origination of the pollen grain) and then, once landed on the flower, grow a pollen tube to deposit the gametes. It is just an unlikely and accident-prone system - yet somehow the earth is covered with these things! Over 250,000 species - the only other taxa with more species in it are the bugs (beetles in fact). So maybe the question becomes: why angiosperms and beetles? I guess the answer for now is, why not?