There are also gearing differences.

I believe Shimano is only offering 11 speed cassettes in Dura Ace, Ultegra, and 105 groupsets for road, and M8000 and M9000 for MTB.

Tiagra is the basic 10 speed group (for the current generation)
Sora is the basic 9 speed group (for the current generation)

Not all of the groups are offered with a triple front option.

I'm not quite sure how Shimano deals with materials. The basic bodies of most of the parts are aluminum, but different models may augment it with Titanium, Stainless Steel, or RUSTY steel. Perhaps not a huge difference, but some difference.

Ultegra rear derailleur jockey wheels use ceramic bushings which should last a good long time. The lowest models of derailleurs (MTB/Box Store) are simply have a hole in the plastic which can quickly wear out. I don't have the details on the spectrum between the Box Store items and Ultegra/Dura Ace. But, suffice it to say that there is incremental improvement from one model to the next.

However, at least with Campagnolo, all isn't peachy with the highest levels which use a plastic composite front derailleur cage to save weight. So, a few levels from the top may actually be more durable.