Language is never stable: it undergoes changes on all its levels: phonetic, morphological, lexical, phraseological, etc.
As for some morphemes, in the course of time they may become fused together or may be lost altogether. As a result of this process, radical changes
in the structure of the word may take place: root-morphemes may turn into affixational or semi-affixational morphemes, polymorphic words may become monomorphic, compound words may be transformed into derived or even simple words.
E.g.: the present-day suffixes -hood, -dom, -like, -ship were in OE root-morphemes and stems of independently functioning words.
The present day English monomorphemic words «husband» and «woman» were in OE compound words, consisting of two stems:
hus-bond-a - õîçÿèí, âëàäåëåö äîìà
wif-man (OE) - woman (a simple word).
In the process of historical development some word-structures underwent reinterpretation: there are cases when simple root-words came to be understood as derived words consisting of two constituents.
E.g.: beggar, editor, cobbler - the representation of such words led to the formation of simple verbs like - «to beg», «to edit», «to cobble».