"Only if they are not among the living on earth,"
But those to whom Jesus was speaking were alive and on earth at the time. He didn't say "you will be blessed".
Blessed are all mericful and pure in heart, and those suffering for righteousness' sake, etc. for all times, past, present and futre.
He didn't say blessed are 'you' (the apostles)...or 'you' (the people) but those (or they) who suffer...the merciful, not 'you' merciful, etc.
The Lord's Prayer says "Thy kingdom come..." It means the Kingdom is not here, BD. genhqhtw is aorist (fuutre,something that is to come or beocme yet)
The Beatitudes spell out what qualities of men, of mankind, are dear to God, and what God intends to do with such men.