Wycliffe made the first complete English translation, working from the Latin Vulgate. The Established Church was unhappy (Wycliffe was a precursor to the Protestant Reformation and preached biblically centred reform), and banned Wycliffe's translation in 1409.
Tyndale came a century later. He was a very gifted linguist, who knew Greek, Hebrew, Latin, French, German, Italian etc (he would have been off the right hand side of MagusAlbertus' IQ graph!). He didn't need an English translation. However, he produced a new translation into English so that ordinary people could read and understand God's Word. He came at the right time to make use of the newly invented printing press and take advantage of the latest research into Greek and Hebrew manuscripts.
Tyndale's version was also banned in England, and he was executed in 1536 in Antwerp at the bidding of Henry VIII.
Later (1604), James I commissioned a new translation for political reasons - he wanted to displace the Geneva Bible which was popular with the Puritans and Separatist's, and also choose wording to support the episcopal structure of the Church of England. However, the Authorised Version did make extensive use to previous English translations, particularly Tyndale's.
The whole purpose of a translation is to enable someone to who doesn't know the original languages to have a version that they can understand. Obvious! However, if after 500 years, the destination language has changed so that people now find the translation difficult to follow, then it no longer meets that purpose. The AV/KJV is no longer suitable for ordinary people. If thou speakest not in 'thees and thous' in they own tongue, then thou shouldest not be using the AV/KJV (or at least, not requirest of others).