You are actually reading the text wrong anyway. The question, "Tell us, when shall these things be? and what shall be the sign of thy coming, and of the end of the world?"
The passage doesn't say that the Lords coming or 'presence' would be the sign.
The sign of His presence would be his presence???....Makes no sense!
The question is "what would be the sign of His coming! NOT THAT HIS COMING WOULD BE THE SIGN!
And you look at what the word parousia means...
presence
the coming, arrival, advent
the future visible return from heaven of Jesus, to raise the dead, hold the last judgment, and set up formally and gloriously the kingdom of God
Look at what Vines says...
lit., "a presence," para, "with," and ousia, "being" (from eimi, "to be"), denotes both an "arrival" and a consequent "presence with." Coming (Noun):
For instance, in a papyrus letter a lady speaks of the necessity of her parousia in a place in order to attend to matters relating to her property there. Paul speaks of his parousia in Philippi, Phl 2:12 (in contrast to his apousia, "his absence;" see ABSENCE). Other words denote "the arrival" (see eisodos and eleusis, above). Parousia is used to describe the presence of Christ with His disciples on the Mount of Transfiguration, 2Pe 1:16. When used of the return of Christ, at the Rapture of the Chruch, it signifies, not merely His momentary "coming" for His saints, but His presence with them from that moment until His revelation and manifestation to the world. In some passages the word gives prominence to the beginning of that period, the course of the period being implied, 1Cr 15:23; 1Th 4:15; 5:23; 2Th 2:1; Jam 5:7, 8; 2Pe 3:4. In some, the course is prominent, Mat 24:3, 37; 1Th 3:13; 1Jo 2:28; in others the conclusion of the period, Mat 24:27; 2Th 2:8.
The word is also used of the Lawless One, the Man of Sin, his access to power and his doings in the world during his parousia, 2Th 2:9. In addition to Phl 2:12 (above), it is used in the same way of the Apostle, or his companions, in 1Cr 16:17; 2Cr 7:6, 7; 10:10; Phl 1:26; of the Day of God, 2Pe 3:12.
The word 'coming' or 'presence' in no way implies that the Lord returned in 1914. When the Lord returns everyone will know it!