Yes!

    MBP Model        Read      Write 
    Jul 2014 15"   1.1 GBps  1.0 GBps
    May 2015 15"   2.0 GBps  1.5 GBps
    Oct 2016 15"   2.9 GBps  2.2 GBps

These numbers come from different posts found on BareFeats[1]. Official claims, and other sources of benchmarks show approximately the same numbers for large sequential data throughput. It is moving from PCIe 2.0 to PCIe 3.0, and an increase in the number of data lanes that have allowed these rapid improvements. SATA III of older models is limited to about 0.5 GBps up and down.

[1] http://barefeats.com/