A guess, but here's my take ...

In the old days, the poker games were almost always self-dealt draw (high) or lo-ball (low) 5-card draw. 3 denominations used: An ante, a basic limit (pre-draw) and 2x limit (after draw). Game structures started with 1-2 limit with 25-cent ante and went up from there:
2-4 limit
4-8 limit
5-10 limit
10-20 limit
20-40 limit (in the bigger places)
and perhaps a 40-80 limit at times / if enough players.

You don't need a $25 chip, and if $100's are around, they are for adding to stack for table-limit, as the game goes faster with minimal change making.

Multiple stacks of $20s is all you need, even in the biggest games.