Sony's a BIG company. Very likely the enginerring group that develops projectors is not the enginerring group that develops televisions. This variation from product category to category can easily develop if there's not somebody at the top who issues and enforces policies of uniformity.

The projector guys want to have an IR jack. They think about it and decide what they're going to do. They don't call the lowly TV guys and ask them how they do it. First, they might not know them. Second, it might not occur to them that the TV guys have thought of such a sophisticated thing.

These days society as a whole values "doing your own thing" more than uniting and acting as a cohesive whole. I'd be surprised if there were anyone at the top at Sony who encouraged or insisted on unity of design and/or style. I'm reminded of a friar named Brother Lawrence, born in 1614, once said something along the lines of "it is not a mystery how much trouble men get themselves into. The mystery is how little trouble they get into!"