See my post above on my situation (we do many small loads) but even if I tried to combine most of our clothes together, I don't know how I could do make that work!
I have a large capacity washer / dryer and do not see how I could fit all of our darks in 1 load. I would say we'd have 2-3 loads
.--- We often have 2 loads, 1 was my "low" week. We re-wear jeans so that probably factors into it.
If we reused our towels (say 2 - 3 times) and combined them with all our socks and underwear, we would still have at least 2 loads
.--- We usually use our towels all week. I can easily fit 5 towels in with all socks and underwear for one hot water load. Often I will have room to add other white/light clothes.
Bedding - 3 loads
.--- Same. To do all the sheets at once is 3 loads. My "low" week was taking into consideration that maybe I didn't get to the sheets that week. I don't have a set day, so sometimes it's every 10 days if that's when I have the time to do them all in one day. Or I might just get to one load with some of the kids sheets.
Delicates/other - There are just some things that have to be separated out. Examples: colors that will bleed (reds, the kids have some really bright blues), light colored clothing that cannot be washed in hot water with the whites or with the darks (I wash towels, underwear, socks, etc on "sanitary" which is extra hot), other blankets (bulky), kitchen towels (even on "sanitary" I cannot wash underwear with kitchen towels...just can't do it!

So, say 3 "other" loads
.--- I don't do any "other" loads. If it will bleed (red) or a new pair of dark jeans I will soak them in the sink and run them under water to get as much out as possible and then usually I will wait until I have a full load of really dark/black clothes and wash them then. After one or two washings I don't consider them to need any special treatment.
We'd still be at 10 - 11 loads. Not at all singling you out tzolkin, I honestly just cannot figure out how people have any less than this! Good for you though
-- 10 is much closer to my 2-6 average than 18-21