Race fit bikes simply had a lower frame stack that allowed for the bars to be low and the rider more aero. The seat tube angle was sometimes just a tad steeper, generally to allow for more power to be put into the cranks.

They weren't so aggressive that they'd be classed as time trial bikes which are not endurance bikes. And are only intended for very fast short rides.

The bikes with more relaxed fit broke down into other sub categories that included touring bikes, which typically had a slightly slacker seat tube that made a little bit more upright position comfortable and was better for grinding away at slower speeds with lower gear ratios and bikes loaded up with extra weight. And of course a touring bike will be expected to have the frame accommodations for paniers and other stuff that might be attached to the frame for touring multiday trips.

I've felt for a long time that the sub-classes that came to be known by many as the only bikes that are endurance bikes, is because they weren't specifically touring bikes, and they weren't specifically race bikes. And the ad people for the websites had no other way to classify them, so they were endurance bikes, just with no special purpose as have touring bikes and race fit bikes.

It use to be common on the bike brands website that they had a category called endurance bikes. Then going into that category, they broke down into racing, touring and other sub categories that had the ad men desperately trying to figure out a name for those categories that would sound magical.

What do you think makes your version of a endurance bike any more endurance than a race bike. People still ride both just as far each and every day.