In plain words
After Vedānta, the Smritis came into being. They are the compositions of ṛṣis rich in sacred tapas and in experience. However, it may be said that the Smritis do not possess the degree of authority that Vedānta has and has always had. Just as other religions have some relation to their own scriptures, the Smritis have an identical relation to Bharatiyas. Just as the scriptures of every other religion are the compositions of great persons, so too must we accept — there is no escaping it — that the Bharatiya Smritis are likewise the compositions of great persons. This very similarity is what other religions and Bharatiya religions share. However, these Smṛtis composed by the ṛṣis have kept changing over the course of time: it has been said that one Smriti is held to be authoritative for the Kṛta Yuga, another for the Tretā Yuga, yet another for the Dvāpara Yuga, and some Smritis for the Kali Yuga. As the ages changed and the community was confronted with many new circumstances, that community's own customs and conventions kept having to change along with them. In keeping with this, since the Smritis are themselves chiefly concerned with a community's own customs, conventions and everyday dealings, it became necessary for them, too, to change from time to time.
This is a matter readers should especially note and bear in mind: the theistic Dharma-sūtras within Vedānta are firmly established,