'Plucking out random narrations'

Often the faithful servants of our marjas stop people from reading ahadith and acting on them under the pretext of "Our ahadith books contain so many ahadith, you can't just pluck out a few random narrations and act on them.". Now even if we disregard the fact that most (if not all) our ahadith books are extremely well organized in the layout of different topics coupled with the fact that in this computer age it is extremely easy to do a keyword/topic search in our ahadith books available online thereby enabling the laymen (i.e. those who were not brought up shamelessly on khums) to find and read all the ahadith relevant to them without referring to a marja/mujtahid, going by the argument cited above by the servants of marjas, even the marjas themselves would then be left unable to issue fatwas. Why is that? That is because MANY of our earlier ahadith books (such as the monumental Madinatul ilm) have been lost and are not available anymore. So taking into account all the ahadith books that have been lost, even reading up ALL the ahadith books available today would count as "plucking random narrations". So where does that leave us? Should we just abandon the religion or is there a solution? Is not it enough to act on what we know from what is available? What do ahadith say?

Thawabul a'amaal wa aqaabul a'amaal

أبي (رهـ ) قال حدثني سعد بن عبد الله عن القاسم بن محمد بن سليمان بن داود عن حفص بن غياث قال سمعت أبا عبد الله (ع) يقول من عمل بما علم كفي ما لم يعلم

My (Shaikh Sadooq's) father said: Told me Sa'd b. Abdullah from al Qasim b. Muhammad b. Sulaiman b. Dawood from Hafs b. Ghiyas who said: I heard Aba Abdullah(as) say: "Whoever acted by what he knew it suffices for him what he did not know."