No need for a blockchain. Distributed software distribution has been around forever, whether it was handing out disks back in the day or streaming warez over BitTorrent now. The problem is trust.
Blockchain enabled transaction processing where the parties to the transaction don't need to trust each other, as long as they are only transacting in goods stored on the blockchain. Once you get into the world of one party having to physically deliver something the other party will use, you're back to the problem of trust.
So until all software runs on the blockchain, no, as long as you still need to install it onto your device, you need to be able to trust the delivery network. You certainly don't need a central authority for that. Normal desktop devices work perfectly fine with people relying on PGP signatures in common Linux distros or something like Chocolatey on Windows and Brew on Mac. But you don't need a blockchain, either, nor does it add any value.
A blockchain allows developers to out-source the running of a globally-available append-only log. Such a log is useful for building something like Trillian:
Ok but how does a globally-available append-only log help distribute applications ? The technology is probably interesting, but it doesn't help solve the problem at hand
If you can securely distribute the hash of the binary, you can probably also distribute a set of URLs representing where the binary can be downloaded from.
Bittorrent would fit well as a way of distributing the apps themselves, as that ecosystem already uses magnet links, and developers could quite cheaply run a node which acts as a seed of last resort.
Bittorrent has everything you'd need for distributing apps: of course the distribution of binaries is there, but it also has storing of arbitrary information, even mutable (http://bittorrent.org/beps/bep_0044.html). This way once you have a version you can fetch further versions by periodically polling the hash that contains the latest version.
Blockchain enabled transaction processing where the parties to the transaction don't need to trust each other, as long as they are only transacting in goods stored on the blockchain. Once you get into the world of one party having to physically deliver something the other party will use, you're back to the problem of trust.
So until all software runs on the blockchain, no, as long as you still need to install it onto your device, you need to be able to trust the delivery network. You certainly don't need a central authority for that. Normal desktop devices work perfectly fine with people relying on PGP signatures in common Linux distros or something like Chocolatey on Windows and Brew on Mac. But you don't need a blockchain, either, nor does it add any value.