You might be right. But if the Celts were playing for the future, they would have kept Fultz instead of basically committing to IT. I have read a bunch of reports saying their goal is to pair Butler and Hayward, and use Butler as an enticement for hayward, and if they cant get both they at least get one. The future is now--by the time the Celts eclipse the Cavs, they may be eclipsed by the 76ers.
Perhaps drafting jackson/tatum is a way for them to hedge. If Hayward stays or goes to Miami, then they have a SF who can develop and be a piece of something better in 2-3 years. If Hayward signs, they can use whichever player they draft in a trade for Butler or to upgrade the front court.
A lot of people seem to think that LeBron will bolt after next year. I dont think we are there by any means, but I dont think it will be too long before LeBron isn't LeBron anymore.