Duke. About the buildings being 'modernised':
- Modernisation should appeal to the younger generation in my opinion.
- Old limestone buildings were annoying: if you put them up 90 degrees from the position they were originally (ie originally 'portrait' and put 'landscape') the skin would exfoliate: it would peel off over time. Limestone is also a problem in the UK I think: many people want to conserve the 'natural' karst (limestone) landscapes, making it difficult to get stone out: large blocks of limestone are rare enough, with so much of it having been used already.

and you seem not to understand why plastic is used so much. Well, I think that plastic:
-is cheap
-is durable
-is light
-is resistant to weather
-is easy to manufacture

The other options are wood or stone.
Wood is:
-brittle (therefore breaks easily)
-in layers, and if part of a layer peels off you could easily cut yourself
-is harder to change the shape of
-is not water resistant

Stone is:
-brittle
-heavy
-hard to make into a shape: to make a stone jug, for example, you have to find a big piece of stone and chip it off. This wastes a lot of the stone and also, if a single mistake happens you'll have to start again.
-requires more energy to even transport to a factory

Anyway, not most products are made of plastic if you think about it. There aren't many plastic chairs, plastic tables, plastic wardrobes, plastic pipes, plastic windows, plastic beds, etc... Almost all materials are used depending on what they are like. The most suitable one is used for the job.