It will be interesting to see if alternative app stores are actually effective.
Let's say a developer gets 1,000 downloads a day from the official Apple Apple Store... but only 50 downloads a day from alternative app stores.
Will it be worth it to keep maintaining their apps on the alternative app stores? They'll have to provide updates to multiple stores... and deal with accounting, taxes, and other stuff from multiple store too. It might be a lot of extra work for very little gain.
Developers might not like Apple's App Store policies... but the official App Store could be the best place sell their apps.
It's not an either-or decision, as in either Apple's App Store or "my" own store. Most developers with any business sense will choose
BOTH... and probably other stores too. Apples store is default. The world is accustomed to using it to find new apps. Some people buy the "Wolf! Wolf!" scare tactics about security, etc such that they may be afraid to try buying direct. Etc.
To your example, if you can have 1050 downloads a day by being in
both stores, why choose to cut 50 off that (or 1000 off that if you are a business fool)? Sell the 1050/day. If getting into a third store adds another 50, take the 1100 sales over 1050 or only 1000.
Is it "worth" running their own store vs. just letting Apple be the one source? Well first, is the 50/day in your example worth it? It's not like running a store on a website is expensive. Websites are dirt cheap once they are programmed and these people are programmers so they probably pay themselves for programming. They sell software so there's no warehousing, shipping & physical fulfillment. It's not like they have to spend a fortune to host software- even the biggest apps we can download don't take up much space.
Whether all in exclusively with Apple or selling on any number of stores, there is
always accounting, always taxes, etc. to do. If I have to register sales to 1000, it's not an enormous burden to register sales of 50 more too. Conceptually, those 50 are more profitable sales, so I will probably be happier about registering them.
Lastly, look to the Mac as an example. There is an Apple Mac App Store and there are tons of developers with their own app stores. Why don't they all close their app stores and only sell their apps through the Apple Mac App Store? It must not be too expensive, too onerous, too difficult, etc. I suspect that many choose to keep their own stores and even sell through many other third party stores too because wide distribution through
many stores is more profitable overall for them than selling through only 1 store.
But- all that written- I definitely do NOT exit the Apple App Store and the 1000/day in your example. Even with Apple taking a big bite of each sale of a product that "I" make
this time, maybe those customers will opt to directly support the developer of a good app by buying the new version next time direct from "me." So I take a big hit to gross revenue in transaction #1 but maybe get ALL of the revenue in transaction #2+... that is, if I'm able to sell
MY creations direct to consumers interested in them.