Did that support and buffs through inspiration, spells etc really help? Did just sitting in a corner and not engaging with the combat significantly contribute to the party's success in the fight much?
Did it seem to be a choice of this specific player, or do you think that any bard would have contributed about the same?
Without the front line fighter, the bard would have been in trouble. That doesn't make the bard useless, it just means he was part of a team and his role was not front line fighter.
Because, once again, D&D is a team sport. All classes fill different niches and have different strengths and weaknesses.