It's no major surprise, the same happened with the internet. There was a huge bubble where everyone was creating websites, each trying to grab as much land as possible and create an audience without any real idea about how they'd make money from it. Then advertisers got onto it and the more popular sites also became the richer sites, meaning more to spend on the already popular site, and so on and so on. Meanwhile the smaller sites that failed to grab the audiences took less money and so didn't stand a chance. Now if I look at my browsing habits I must visit less than 10 sites on a regular basis, reading the news, sport, social etc.
The trend with apps is almost identical. I already only use about 5 or 6 apps and rarely download anything else, my app habits are the same as my browsing habits.
Both follow the same trend and in my opinion it's because both are limited to how they can make money, direct or indirect. Direct is obvious, customer buys app, or customer purchases within app. The indirect rout has a lot more room for innovation with advertising, marketing revenue share promotions etc but they all boil down to the same thing, incentivisation, making money when the customer spends somewhere.
I would like to be able to program as I would like to break this model up as there are other ways to make money without scamming people out of their cash with in app purchases aimed at kids, or gathering all their information and selling it on, one day I'll read my 'for dummies' book I've had for a year without opening :)