There was a time that single shot pistol and kits were a fraction of the price of revolvers. Those kits were made in Japan or Spain and the quality was just fair. To a certan degree, the economy of scale has an affect. Making a 1,000 rvolvers on jig used for 30 years canbe mad pretty cheap, compared to new tooling to turnout 200 single shot pistols.
COWBoy actionshooting has created a renewed interest in C&P revs. Single shots flooded the market 30 year ago, and are still ot here pretty cheap.