I think that planned obsolescence would absolutely slow down tech progress. A washing machine manufacturer has little incentive to make his product better when

I think that planned obsolescence would absolutely slow down tech progress. A washing machine manufacturer has little incentive to make his product better when he knows that his customers will keep buying his washing machines anyway. Creating "new" models could be as easy as giving the thing different paint job. It then makes difficult to sell, for example, graphics cards because customers that wanted to buy a card now have to buy a washing machine because it unexpectedly broken down and may then resort to buy cheaper model from competition. The manufacturer will end up with less money to pour into R&D. I wrote this with the assumption that the washing machine company shares their market with competitors employing the same strategy, entrance to the market is extremely hard because dominant players own the patents which require huge up-front investment with uncertain results due to the rivals' strong market position.