My kids have all followed very different patterns. Ds1 was nursing a lot at 10 mo, probably 8x a day, and he moved down to about 4 times a day by 16 mo (am, before nap, after nap, before bed). He really wasn't eating many solids before 14mo, so he was nursing for a lot of his calories.
Ds3 eats solids a lot better and he nurses about 4-5x a day now at 16 mo (am, before nap, after nap, 5-5:30 pm, bedtime). He has food allergies so I am counting on the breastmilk to fill in gaps in his diet.
Its true that my supply has dropped when I cut out pumping sessions if its not replaced by nursing. But I find that fewer nursing sessions tends to mean they eat more milk less often but I don't feel its harmed my supply.
Ds1 (2006). Ds2 (2010). Ds3 (2012).