I know of at least 3 sidechain projects in the works. Do you think a sidechain will be worth less after a hard fork brings more capacity? Do you think Blockstream will be held legally accountable?
The hard fork itself doesn't bring the capacity, the miners deciding to mine bigger blocks does. Sidechains should be fine if they are able to compete on equal footing with native tx, there are likely many cases where they can be successful in that.
Blockstream will be held accountable by the market, the miners that process transactions, and the users/customers that pay for their product/service. I wish them success as long as it is attained by competitive, not coercive means.