Why does Spanish often drop subject pronouns and English doesn't?

Like in English, Spanish possesses subject pronouns that often precede the conjugated verb. These are:Yo - I Tú* - You (singular, informal)Él/Ella - He/sheNosotros - WeVosotros* - You (plural, informal)Ellos/Ellas - TheyHowever, unlike English, these pronouns may often be omitted leaving just the verb; as such, the verb phrase 'we do' may appear in Spanish as 'nosotros hacemos' or simply as 'hacemos', with the 'nosotros' dropped completely. This is due to the complex nature of Spanish verbs. In short, verbs in Spanish change their conjugation (end syllable) depending on their subject. This also occurs in English but to a much lesser extent. Let us consider the verb 'hacer', meaning 'to do'. In English the conjugations are as follows: I doYou doHe/She doesWe do You doThey do Compare this to the Spanish 'hacer' which conjugates as: (Yo) Hago(Tú) Haces(Él/Ella) Hace(Nosotros) Hacemos (Vosotros) Hacéis(Ellos/Ellas) HacenAs we can see, in English all the verbs have the same form, except ‘does’ for the ‘he/she’ subject whose conjugation varies slightly. In Spanish this is not the case; all of the verbs’ conjugations differ depending on their subject and each subject has its own individual verb form. Thus, the subject pronoun is not required for the reader or listener to determine to whom the verb refers; this meaning is intrinsic to the verb form and the subject pronoun may be omitted. Since English verb conjugations are not this complex, the pronoun is obligatory for the subject to be known, hence the difference in verb structure. *There are also the formal equivalents of these, Usted/Ustedes, however introducing these will likely unnecessarily complicate the situation and therefore are subject of later discussion.