I can imagine a situation where the transactions are of such a big value that even the 7 transactions per second are enough to pay for the whole system sustenance. But yeah the system currently burns resources on a level comparable to gold mining (https://medium.com/@zby/proof-of-work-8d8265def194) - but it is much less useful than gold (for value store).
Yes and no. 1 Bitcoin is worth more than an ounce of gold ($2340 Bitcoin to $1215 ounce of gold). But the value of all outstanding Bitcoin vs all mined gold is much lower ($39 billion all Bitcoin to $8 Trillion all gold).
What are you really asking about? What is historical value store of bitcoin? The value stored in bitcoin is still orders of magnitude less than that stored in gold.
Sure the exchange rate of bitcoin has grown much - but it does not make it better value store now, rather the opposite.
It is too early to judge. A good store of value probably shouldn't increase in value 3-10x each year. If I were to put $1000USD in gold today, I could be fairly sure that in 30 years it will still be worth, at least, $500USD. If I were to do the same with bitcoin, I have no idea what would even happen in 5 years.
