Whatever licensing deal Netflix had for Last Man Standing likely expired, and it was either decided that renewing it wasn’t a good option, or another company was already waiting in line to pick up those rights.
Hulu, for instance, has only had Season 6 of Last Man Standing available for its customers, which was likely limited by Netflix’s deal.
While Netflix customers always hate to see a beloved show or movie bite the streaming dust, it isn’t something that happens with malice in mind, as it’s all about the financial bottom line.
As such, it wouldn’t be surprising to see Seasons 1-5 showing up on Hulu in the near future.