1) It will grow by 1GB/day only if the blocks are full. Which they won't be for a long time, unless that branch becomes much more popular.

2) 8TB drive is $175 on Amazon. That alone can hold ~1 thousand days of full blocks. That's almost 3 years worth of blocks. By then the HDD prices will likely be even lower.

3) If some regular user will want to mess with the whole blockchain (which is such a strange argument, most don't care for it), downloading 8TB of data takes less than 18 hours on a gigabit connection. It will take years to get to 8TB.

4) There's no real objection to SegWit, as long as it comes with the large blocks. But consider what happened with Segwit2X - as soon as Segwit support solidified, a talk of ditching the 2MB extension started, a classic bait and switch. It's all over /r/bitcoin.