In every industry there's cyclical trends just like business and economics as a whole have cyclical trends. Website industry and internet are no different.
There are periods of consolidation and there is periods of specialization/diversification.
Let's use an example: Grocery Stores
In the grocery store industry things in the 50's and 60's were very specialized and diversified...naturally several specialized firms begin to separate themselves from the rest and begin to eat up other competitors in the area. Thus the consolidation phase within the industry begins. Eventually the industry becomes very consolidated which we saw in the late 80's and throughout the 90's. You had Walmarts, Meijers, Krogers, etc. who owned a large portion of the market share. Then the consumer naturally wants change. They like specialization. And all of a sudden you start seeing specialized markets open up. Health stores, vitamin stores, produce stores, etc. popping up all over. Thus the diversification/specialization trend begins to happen again.
The perfect example of a store who started in a specialization phase move into a consolidation phase is Whole Foods. They started as a specialized store and that's why they were so popular and successful. They separate themselves from the rest, start quick expansion, and suddenly you start noticing consolidation within a previously specialized industry.
This is what happens in the internet/website industry. Right now we are going through a large consolidation phase but eventually you'll see a specialization trend start up again.