Remember this ad?
IBM BladeCenters were revolutionary at its time. System Administrators would know that one of the largest expense when building out a server infrastructure is real estate costs. Shrinking racks of servers and consolidating into blade servers meant you could put more hardware in less space. However, they were expensive and had their fair share of skeptics. Adopting a proprietary backbone simply meant you were investing into a brand and hence subject to vendor lock-in.
Then came virtualization. With more powerful CPUs, cheaper RAMs and more cost-effective storage solutions, we are now able to cramp more servers into a single server. Other pieces of traditional server infrastructure, e.g. network and storage, could be "software-defined". The server footprint very much "vanished into thin air"!