Israel was never expecting a return. The Jews living in the first century believed that their Messiah would someday arrive and rule forever. It would be an arrival; a one time arrival. They never expected their Messiah to come, leave, and return a second time at some point in the future. This is how we know the question being asked in Matthew 24:3 isn't about Jesus' second coming and why His answer wouldn't relate to that. The entire series of the questions asked revolved around "these things," the destruction of the temple, the end of the age, and Jesus ruling over His kingdom. This is what the disciples asked about, and those things occurred in their generation.
"Now as He sat on the Mount of Olives, the disciples came to Him privately, saying, “Tell us, when will these things be? And what will be the sign of Your coming, and of the end of the age?” (Matthew 24:3 NKJV)
The Greek word for "coming" is parousia, which means arrival or presence, not return. Most English translations of the Bible translate parousia as coming, but “presence” is a more true and literal to the actual meaning.
View attachment 315006
"And when he is sitting on the mount of the Olives, the disciples came near to him by himself, saying, 'Tell us, when shall these be? and what is the sign of thy presence, and of the full end of the age?'" (Young's Literal Translation)
If the question being asked by the disciples was about Jesus' return or second coming, the original Greek manuscripts in all likelihood would have used a term such as "epanerchomai" instead of parousia.
Thayer's Greek Lexicon
STRONGS NT 1880: ἐπανέρχομαι
ἐπανέρχομαι; 2 aorist ἐπανηλθον; to return, come back again.
Strong's Exhaustive Concordance
come again, return.
From epi and anerchomai; to come up on, i.e. Return -- come again, return.