After 18 months conscription was brought in in Great Britain because the pool of volunteers had run out. If that had not been the case conscription would not have been imposed.

If history academics reach a judgement that mistaken tactics which resulted in enormous numbers of casualties for no gain were the result of decisions which were reasonable in the circumstances, that is interesting - but it does not alter the fact that these tactics were in fact the wrong tactics. And that is what matters, not the question whether or not individual blame should be given to the generals involved. They did of course escape any such blame at the time, and lived out their lives free from any adverse consequence.