Provided SideChain are not introduced the cost to mine empty blocks becomes prohibitive, and can approach infinity, the incentive system as is rewards corporation.
I think this recent engagement with Jorge provides a window into just how hard the next stage of bitcoin adoption will be.
Many of us leap into Bitcoin once we understood it, because we were already politically aligned to it's ideology and saw a chance for Bitcoin to realize what we had already been looking for.
However this is a very small pool of people compared to the population at large. The next pools of people are those who are indifferent and those who are outright hostile/opposed to what Bitcoin represents, with the majority most likely being hostile.
Jorge is good example, he is a CS professor being paid by the state to spread misinformation. If you were already politically aligned to believe in government control of money (so they can "adjust" the supply "grow with the economy"), you are already motivated to be against Bitcoin and would accept Jorge's line of reasoning without question because it agrees with your world view. Expect more and more of his type of "analysis" to appear in credible sources.
To overcome this very real adoption hurdle I think Bitcoin can only win by becoming more and more functional and needs the ability for market participants to create and explore new functionality.
This is why I believe the sidechains are interesting and should be pursued (the concept not necessarily the current implementation).
I went quiet during the last round of sidechain discussions since it's hard to properly discuss it in thread format, but I've come to believe that economic interests by participants is what will enforce proper behavior and make the concept work. A lot of the concern seems to be poking holes in what is possible technically with sidechains, but I think economic interests would win. BTW, I believe the same is true for Bitcoin, it is economic interests that make Bitcoin work, not technical. I'll try to expand on that later.That said I've come to completely agree with Adrian and cypherdoc that sidechains will ruin the incentivization system of Bitcoin, which is mandatory for it to function as an independent and decentralized system.
If sidechains are implemented as is, I would seriously question the viability of Bitcoin to survive after block rewards become dependent on fees.
However I think there are straightforward solutions to this, largely by structuring them as childchains and not sidechains. Children chains should be forced to merge mine with their parent chain, in effect contributing all of their hash power to the parent and making the parent have the sum hash power of all children, whereas the a parent chain can mine on it's own and does not have to merge mine with anyone else. I'll try to describe this in more detail later when I have time, and then you guys can tell me where it's all wrong
TL;DR I think the concept of sidechains is needed for the next stages of adoption, but is unworkable in it's current form. So we need to find and propose the right form of a sidechain concept.