You don't go buy a coffee with gold nor a car with tin; yet there're more coffees being sold out than cars and within this BTC we only get gold.
I know this moves with the greed of old miners, believing that a secondary line would drop the value of their bitcoins... still, is just a matter of put it in the right perspective to prevent such thing.
And, again, a secondary block chain would give a boost of another "gold rush" for it... maybe shorter than the actual block chain as now there're a lot of miners equipped with top edge GPU, something I don't recall to see last year.
Are there any ideas for how exchange would happen between the two block chains? Is there some way to facilitated chain1-to-chain2 exchange such that it will not become a completely independent currency? I think two indpendent bitcoin currencies would be damaging to the chances of expanding this into merchant trade. Merchants would have to decide which to support.
PQ = MV problem can be addressed by increasing V or M, or some combination. The 2nd chain idea addresses M, but the problem is then we will have PQ = (M1.V1) + (M2.V2) and it will get complicated. Increasing V will help imo but I do not yet have a vision on how to get coffee for my bitcoins. What about just increasing the number of BTC awarded to miners? That may not seem fair to last year's miners, but we have to consider whether the recent large BTC price rises (deflation) is a long term threat to BitCoin overall. Any currency, whether it be fiat, gold, Medici bills of exchange or immovable rocks will not succeed if there is not a reasonable amount of price stability (neither too much inflation or deflation). It just becomes too impractical for merchants to manage long term, they spend more time adjusting prices than conducting business. The miners might conclude some price stability is equally in their interest.