1. Blockchain is useless without bitcoin.

2. Bitcoin is the first ever absolutely digitally scarce technology limited to 21 million. The supply cap of 21 million cannot be increased so its value should theoretically keep increasing.

The technology IS bitcoin, which is a lot more than just blockchain (it's a protocol, including pow, consensus etc.). The currency is BTC. The fact that it has a price, in fiat or other terms, is due to the fact that it has value, which is what allows it to act as a currency. If it had no value it would have no purpose and would cease to be.

That comment supposes that blockchain, at it’s core, is anything more than just a datacenter that’s split over thousands of operators rather than a single centralized entity.

So blockchain (in many instances) benefits from not being operated by a single centralized entity, but does so at the expense of economies of scale. In other words, centralized datacenters are a lot cheaper and easier to operate than distributed ones.

So we have to ask ourselves, are people really going to spend exponentially more money on applications that aren’t really worth all the extra cost associated with distributed ledger technology?

They will for decentralized money (i.e., Bitcoin). I don’t anticipate in the long run that they will for much else.