How can you say "sidechains don't address the scalability problems" when you don't even know what sidechain technologies are on the drawing board ?
And what is the point of sidechains anyway if they don't address the scaleability problems amongst others ?
The whole idea of them is to experiment with variations and innovations that would otherwise go into bitcoin but which are potentially too radical to hardfork without maturing for a period outside the native blockchain.
It surely follows - conversely - therefore, that if a blocksize change can help bitcoin scale, it can do the same for a sidechain.
The purpose of sidechains is mainly to allow for unique testing of controversial code and possibly unique tokens that still have the strength and security of all or most of the main Bitcoin network.
The reasons sidechains don't address scalability problems is that they could add extra transactions to the bitcoin blockchain due to many new sidechains being introduced to facilitate everyones' projects. I understand your point that there could be a sidechain introduced to alleviate some of the Tx on the mainchain(I.E... microtransaction sidechain) , but what you also have to account for is the flurry of new transactions that will now occur when individuals jump on and off the sidechain and between the hundreads of sidechains thus using the main chain. This is traffic that is normally being handled off the chain or by alts right now. If you are a new alt creator you may very well want to create a sidechain instead of your independent blockchain to get all the benefits from being a sidechain.
