In principle Bitcoin's engine can support any price. The one big issue is electricity consumption. Mining is driven by profit which is mining income less electricity cost (and some overhead). If the price of Bitcoin increases there is more income and hence there will be more miners. Sadly it does not even matter if miners get more efficient as we will just have more of them, driving the difficulty and hashrate up. Today mining has the footprint of Costa Rica (+/- depending on which estimate you take). If the price rises to 250k$ Bitcoin's footprint will be between that of the Philippines and that of Australia (depending on the estimate you take). One halving taken into account here. Is it politically feasible to allocate that much electricity to Bitcoin Mining? Is the level of security justified to protect the market cap (or is it too high driven only by profit seeking miners)? Finally, Bitcoin could change the consensus algorithm but would it still be Bitcoin then?