Ultimately, the price as of now is partly determined by how many bitcoins got lost for good during the Mt. Gox collapase. If none at all, then price might theoretically be higher than it is now since Bitcoin wouldn't have got so much bad publicity as it really got and many people who lost their at that exchange would likely invest more heavily later. On the other hand, though, if many coins got lost, the price today might in fact be higher thanks to constricted supply
what do you mean by "lost"? is it like destroyed!
Lost means that the coins that got lost will likely never come back "online" (similar to 1M of Satoshi's bitcoins)
in any case i feel like you are forgetting about the fact that price was pumped to $1200 in 2013 by mtgox and it didn't go there on its own. which means it had to come down.
so irregardless of the bad publicity of the pump and the bubble that formed those years, the price had to come down. market was just not ready for that kind of rise.
the same thing is true for now, market is not ready for a higher price and it won't be ready for it in the near future either. it is ready for $1000 for now and possible $1500 to $2000 by the end of the year based on the adoption we are seeing these days.
anything more needs more too
It likely needs a lot more
But it may not in fact need a block size increase, specifically. The price today (and still more so in the Mt. Gox days) is determined by the balance of supply and demand at major exchanges (like Bitstamp and cronies), but to trade there you don't need the blockchain altogether (only to deposit coins into your exchange account) and therefore the size of the block is irrelevant. If you, nevertheless, think that the price is determined by real trade in any significant degree, good luck to you. Further, the transaction jam we see every now and then is mostly due to spam transactions, and if they were effectively dealt with and gotten rid of, there would be plenty of room left