I must have read this idea somewhere. If anyone could suggest where, let me know. The idea is this: The variations in appearance of script over the centuries prior to the invention of moveable type (in the European West, that is) were due to a number of factors (e.g., what was considered appropriately "official"), but NOT to any overt theory of visual "ideals."
Then along came moveable type, and in fairly short order (the decades immediately following 1440) the mechanical possibility of creating many different kinds of very sharp, tiny and delicate lines and shapes-- something not really possible when writing by hand but very much within the capabilities of somebody good with the tools and skills of a jeweler, goldsmith, machinist, etc. And along with this, the ability to lay those fine lines and shapes on paper quickly.
This shift in what could be accomplished mechanically, so the argument goes, actually created the conditions which made it possible for type "theories" such as rationalism and romanticism (and later, modernism) to emerge and flourish. So, and here's the clincher, if any of this makes any sense: the mechanical technologies made the theories possible. That's just such a sweet conclusion, but I am afraid maybe it's a little bogus.