The Mishna cites a machlokes Beis Shamai and Beis Hillel whether the bracha of borei pri hagafen is made before or after the bracha of kiddush. Beis Hillel says that we first make a borei pri hagafen, and Beis Shamai says that we first make the bracha of kiddush.
In the Braisa, Beis Hillel offers to reasons for the bracha of hagafen to come before the bracha of kiddush. 1. The wine is the cause to make the bracha of kiddush - if there would be no wine the bracha of kiddush wouldn't be said. 2. The bracha on the wine is considered tadir, more common, than the bracha of kiddush.
The Tzlach points out that both rationales of Beis Hillel are problematic. The first approach assumes that without wine or bread, one wouldn't make kiddush. Although Tosafos in Pesachim 106a questions whether m'doraysa kiddush requires a cup of wine, most rishonim understand that m'doraysa one doesn't require anything for kiddush, just to be mekadesh the day with words. How then can Beis Hillel say that the wine causes the kiddush to be said, since one would actually make kiddush even if they had nothing to make kiddush on? The second approach of Beis Hillel is also problematic. It is fair to assume that a mitzvah d'oraysa is considered mekudash when compared to a d'rabonon. The gemara in zevachim 90 concludes that between tadir and mekudash, we don't know which should be first, so we assume they are equal. Therefore, although hagafen may have the tadir advantage, kiddush has the mekudash advantage so the logic of Beis Hillel that tadir demands that hagafen come first, is not accurate.
The Tzlach explains that we are clearly assuming that the person had already davened and fulfilled the d'oraysa obligation in their tefilla, and the kiddush on the wine is only d'rabonon. In such a circumstance, both arguments of beis hillel are valid. Based on this the Tzlach concludes that women who don't daven ma'ariv or someone who didn't yet daven and is making kiddush on wine, should say the bracha of mekadesh hashabos before the bracha on the wine since in that cas e both arguments of Beis Hillel don't apply. The hagahos of the shoel umeishiv disagrees with this conclusion and explains that the rationale offered by the braisa is what the chachamim used to organize the order of the brachos. But, once they say that hagafen comes first (since they are assuming most people who are making kiddush have already davened and fulfilled their d'oraysa obligation), it will always come first, even for people who have not yet said kiddush in davening.