DASH number of unique transactions per day:  about four thousand.

Bitcoin confirmed transactions per day:  about 230 thousand.

It's not the block size, it's the maximum block size.  DASH is also a younger project with very few transactions, so the blockchain is very small in comparison.  Not to mention that in DASH, full node users are rewarded, while in Bitcoin they're just volunteers. 

I don't think it's a fair comparison.

Plus, you don't know that it can't get to 2mb.  While they're not actually signalling for the code yet and they might not carry out with the hard fork anyway, it seems like shitloads of pools are supporting SegWitx2 right now.