yes but if they'rre trained and bloody minded they can still stop an advance - rather like the episodes in WW1 and the US Civil War when people exploded bloody great mines under the opposition front line.
In most cases someone (normally an NCO) rallied the survivors and reoccupied the devastated area in time to slow or stop the oncoming attackers... Also several occurrences in Normandy in '44.... and we won't mention Casino ................