Let me suggest some reasons.
1. There's only 10 of us at most regularly posting here and the interest range of countries is quite narrow, although there has been some nice variety, a high percentage of coins so far are USA, which is back to a few state coppers, the UK is pretty much in hiatus until the 1750s as we back before the conders and the only coins issued 1760 - 1785 were mostly fractional guineas and 1 shilling.
The late 18th century is also an era where many modern states like Germany and Poland were barely existing, and also when coins become much more expensive except coppers.
We are kind of in that no mans land between Modern (1800 -) and Medieval (To about 1650) coins and most silver and gold of this era unless really worn is expensive and most copper and billion is either scarce or worn.
Generally (But not universal) the Industrial era of the 1800s saw coins issued in massive quantities for the first time since the Roman empire and the early 1800s was really the rise of new nation states especially in the Americas. But this era we are in is different.
Lets look at the early 1780s, most of the Americas is controlled by Spain, Britain or France (Except Brazil which is Portuguese) that is 50% of the world with 4 countries/empires, Russia is a big chunk, China is a big chunk (And they mainly just had one coin until the 1880s - the holey "cash coin". India mainly had coins in unreadable scripts for most of us (We really need an Indian or Middle Eastern numismatist showing coins of their countries). Most middle eastern coins were either Ottoman (Hard to find before about 1844) or Persian.
Many parts of the world did not have coins or were not using them until the late 1800s. Places like Australia, New Zealand were barely discovered, most of the South sea islands, Micronesia, big chunks of SE Asia had nothing or chunks of metal like Att and Baht in Siam. Most of Sub Saharan Africa excluding the cape and a few coastal ports had no coins, and even colonial outposts mostly had serious coin shortages until the arrival of steamships around 1850 - 1880.

Even Europe was bitsy at the time, yes you had the UK, France, Spain and Russia, but most of Germany, Italy, Balkans and Eastern Europe was tiny polities, princedoms, dukedoms, countancies or part of some empire.

Finally before the Industrial revolution, 90% of all people were bone poor and living at subsistence level (Bear in mind 99% of all coins minted in Russia before 1700 were dengas (½ kopek) and Kopeks, not big rubles. Even in parts of England, the average peasant before about 1700 saw no more than a few pence in their lifetime, big silver and gold existed only from the mercantile classes up.

Finally we are far back enough now to enter the pre industrial world, a world were most people had limited resources and limited social interaction, most were illiterate as well.
The period from 1800 to 1900 probably saw the greatest change in human society ever.

Personally I only have a hand ful of coins to go, but they are all stunners and you guys will love them.