Does anyone know what economic conditions cause a market to transition from being car/house-like (no fixed price, annoying sales process) to what is normal for cheaper products in first world countries (more-or-less fixed prices, less aggressive selling)? Is it related to products'scarcity?

From my own experience I know that even products that normally have fixed prices in the first world (cell phones, bikes, anything really) are sold more like cars in a lot of developing countries where bartering is the norm. You might find them available for drastically different prices even in the same locale and it is frequently necessary to waste time and energy keeping track of the going price for a particular product that you are considering buying.