We got new toilets at home last year. Without fail, I have to full flush at least twice for solids. They simply aren't strong enough to do the job in one go like the old ones were. Such a waste of water.
The older style toilets I remember as a kid just worked. One flush would properly and fully clear out anything that didn't clog the darned thing.
The new toilets barely flush properly with two flushes, and I still wonder how much is left behind in the backwash.
Anecdata is anecdata. It's most likely that some toilets are just bad and some are good, regardless of flow amount.