I don't see anyone I know needing more than 1 TB in 4 years, yet, if they wanted to run a bitcoin node, they would run out of space with their regular 1 TB HD
No. They wouldn't.
The math is quite simple and very clear that we won't exceed 1TB in 4 years unless block sizes get MUCH larger (more than 4X today's 1 MB size). They are currently limited to 1 megabyte.
Bitcoin has been running for 8 years now and the blockchain is less than 90 gigabytes. If we grow at double that rate in the next 4 years, then the blockchain will only be 135 GB.
If EVERY blocks is COMPLETELY full at 1 MB per block for the next 4 years, it will only grow to 300.4 GB.
If block sizes are doubled with a hard fork, and EVERY block is COMPLETELY full at 2 MB per block, it will only grow to 510.8 GB.
Try the math yourself.
Take the size (in megabytes) you think the block will grow to after a hard fork. Multiply that by 144 (blocks per day). Multiply that by 365.25 (average days per year). Multiply that by the number of years you want to know about. Add 90,000 and the result will be the size of the blockchain (in mgabytes) at that time.