Srilankans were very clear about drawing the match from the very start, guess they didn't even think about chasing the target. 2 back to back draws seems boring in the modern times when teams are pushing for result. Was reading somewhere that its the first series after 2015 which ended up all draw games.
It is a fact that after the introduction of T20 cricket the game has changed a lot and anyone who has the ability to play a standard patient innings is rare in the game and i do think the T20 has changed every player and so is the reason we are seeing fewer draws in Test cricket as well. The West Indies and Sri Lanka team right now might not have players who are molded in the T20 format and so is the reason we are not seeing any aggressive game play.
I don't think the outcome has anything to do with influence from T20. It was actually very simple. It looked as if both the teams were happy with the draw. None of these two teams made a serious attempt to chase the total or get the other team bowled out. The spectators lose out in the end, as it looked as if the players themselves were bored with the match and was playing just because it was scheduled by their respective boards.