That sounds like a plan to me. Be opportunistic in accumulating picks, talent, & flippable assets while still retaining long-term salary cap flexibility. It only appears non-committal because of the strong starts (a testament to our coaching staff & roster talent at the time) followed by the trade deadline sell-offs, which was always the plan. Allow players to build/restore value & turn them into long-term assets. Lauri is no different. They may have considered pivoting due to his breakout but clearly did not find an acceptable path to do so.
Plus, this is Ainge we're talking about. He's here to cap off his legacy by leaving a storied but championship-less franchise with a potential dynasty. If these next two draft classes had lined up with when he took over, I have no doubt that we would have fully tanked right out of the gate. Instead, Ainge bought time. Preserving (some) patience from the fan base for when we truly tank, as well as the reputation of a consistently competitive franchise, all while allowing for more time to accumulate talent/assets & build/restore trade value. Also, timing it perfectly to allow for our current talent to incur the struggles that come with development, simultaneously putting us in position to acquire that missing superstar.
I can see why it may appear that there is no plan but do you really think one of the greatest gms of all time is out here just winging it? Or that an NBA owner would even allow that? Maybe for Ainge but I doubt it. And when Lauri was acquired, do you think they viewed him as a long-term piece? Or do you think they viewed him as an undervalued asset? And even if they did eventually begin looking at him as a potential long-term piece (relative to our core/future assets - clearly he can be a long-term building block in the right situation), why not dispell the rumors & say we're not trading him?
Imo it's because plan A is to trade him for a haul. As it has been all along. And even if it wasn't, it seems pretty clear that it is now. Plan B might be to keep him long-term, but right now Ainge is just maintaining leverage by keeping the appearance of not wanting to trade Lauri. As any good negotiator would.