i communism there would be (strictly speaking) no private posessions and no money.
Im sorry but this isnt true. Communism is an economic system and there is money in that system. The money is used to aquire personal possessions. There are no private businesses or industries. They are all government owned and operated.
why should this system put restraints on creativity?
That being the case there is no need for competition because they are non-profit. Introducing competing versions of the same products creates unnecessary inefficiency. Efficiency is the holy grail in communism. Therefore you end up with very little variety in communism. Why would you put out products that are less popular then other products if you had no incentive to do so? Putting out different products of the same products means you have to spend additional money to develop something that you already have. You have to pay engineers to do the same thing over and over. You have to pay engineers to build altered manufacturing equipment to build a slightly different product. Why would you do that? What incentive would the government have to do that? The people already have one version of the product.
In capitalism we have a similar philosophy in corporations. Corporations are efficient because they eliminate management positions of several companies and consolidate them. This raises the profit margin. Back in the late 1800s and early 1900s we had massive companies called trusts. They monopolized the market and eliminated their competition. Among the many characteristics they had was diabolical efficiency. They violated the capitalist doctrines of competion and free market though so the government put a stop to them.
Why cant communist nations simply import products to increase variety? Well they can, but as I already stated Communist nations must avoid importing capitalist products. Capitalist consumer products are vastly superior. That being the case communist products are not consumed by capitalists because they suck. The problem this creates is communist nations would end up bleeding off all their money to capitalist countries and their poducts would go almost completely unused. At some point the system breaks.
In case you wonder why communist products suck I will explain.
There are several reasons communist products suck. Here is the first reason. In communism you always have shortages. This is because worker productivity falls over time. There is no punishment or reward for your work ethic. No one is motivated to put out the effort so most people don't. This leads to shortages because people stop pulling there weight. One person can't make a difference. The ones that are pulling there weight are eventually pulled down by the ones that aren't. They realize the futility of working hard. This creates a very poor work force that snowballs into despair.
The second reason communist products suck has already been mentioned. It is because there is no incentive to improve existing products. Improvement requires money for Research and Development. Since very few endeavors are worthwhile there is very little R&D in consumer products. In reality since communism and capitalism are diametrically opposed they are constantly seeking newer and better weapons. This money for R&D which would be essentially wasted on consumer products is eagerly put into use on Military projects, which are the most useless products of all for an economy. The only benefit military projects provide is advancing technologies that may have civilian applications but in communism civilian applications are only done on an as NEEDED basis. Playstation II is not needed in communism. Nor is a flat plasma HDTV. The Lord of the Rings and its special effects arent much of a use either. Creativity DOES exist in communism. But it is limited by money.
The ultimate difference between the two systems is that in capitalism people need to be responsible for themselves. They can get fired from their jobs and lose their homes. They can feel as though they are underachieving and seek to better themselves. In communism people are not responsible for their own prosperity they depend on everyone else much more than they depend on themselves.
It is true that in capitalism we depend on everyone else to make the system work but our system works because the individual feels the effect of his failure much more than the community.