There are two reasons for the decrease of focus on Christ in Christmas.
1. The enemy is intentionally dumbing down this idea. Atheists celebrate Christmas with no idea who Santa is, or what is the origin of a hot-cross bun.
2. Christians who figure out that Jesus was really born sometime around late September, early October. And, Christmas is really one of the pagan celebrations (winter solstice) integrated into the Roman (mandatory) "universal" (read: everybody's religions all mixed together) church. Somehow, the protestants who saw falsehood in that church failed to execute a complete analysis, comparing scripture to custom... and the pagan celebrations still reign in stead of the holy days Jesus celebrated. So, Christmas remains a celebration of careless, inactive Christians. These rarely stand up against the works of the enemy. The Christians who are out warring for the kingdom are not going to defend a work of the enemy. In the future, the day may very well return to being called "winter solstice." Who knows?