This is what sidechains mean to me.
Side chains are not even the slightest bit needed to use BTC as a reserve currency.
They have absolute need for a reserve currency because it eliminates the need for such backing as POW or POS.
Now they still will need POW, but only to support Bitcoin. Not (necessarily) to support their own core infrastructure needs though many probably will leverage this anyway.
It's nearly prefect the way it is. 7 tps is plenty for that. Probably an order of magnitude or two overkill in fact.
That is in no way clear to me. With activity of the magnitude I'm visualizing individuals just exercising the peg to the backing store could be significant not to mention the various balancing that the multitude of sidechains will be wishing to perform on the actual backing store itself. Also, of course, I see a role for individuals and organizations using native Bitcoin raw, but mostly just for critical or 'difficult' tasks.
One way or another, pushing up into where the transaction fees are a factor before trying to push a harmful and potentially devastating hard-fork makes a lot of sense to me. If the 'new paradigm' that Bitcoin transactions are ever-subsidized for nearly free use by the masses is where people's heads are at, they should say so. Piss or get off the pot. It's disgusting and embarrassing to see these supposed 'principles' of Bitcoin be milked for marketing reasons long after they've exceeded their shelf-life and become absurd.