From experience with MTB and CX bikes, I'd say a triple for off road is pointless because you never need that wide a gear spread and either 1x or 2x are the optimum. My current MTB is a 2x9 with a bash ring in place of the outer triple chain ring and I rarely run out of gears on top, but regularly grab the granny ring. For CX single ring with good retention makes a lot of sense since any hard climbs will be a dismount and run up anyway. Also the newer 11 speed MTB groups have more than enough range for average conditions with a 34-36T front ring and that both removes a failure point and provides a convenient spot for the dropper remote.
I don't see the value of 1x for road use yet since the higher speeds combined with climbing necessitate 2 rings for enough range, although the advent of wide range 11-30 and 11-32 road cassettes obviates triples except for heavy touring bikes and tandems.