Before the fork from the legacy chain you needed serious server hardware to run a witness node. Steem Inc made a few efforts to reduce this as they were running out of money before they sold out.

Later, when I first started Witnessing you needed a powerful PC with 32Gb+ of RAM and 1Tb of NVME to run a witness node. Now you can run one on a Raspberry Pi!
@blocktrades and others have made huge strides to reduce the hardware requirements to run a Hive nodes and created all sorts of efficiencies.

I suggest you read the technical reports they put out every so often that detail this.

So I have followed this trend for a long time.