LISK already has a built in DAO of sorts in the form of the DPOS 101 delegate system.

With LISK you could vote for 101 delegates who give the majority of their funding to LISK DAPPS.

So at a Billion dollar valuation ETH is spending hundreds of millions of dollars on mining while LISK at the same valuation would be spending much less, due to lower inflation & more importantly at the end of the year, instead of all that money having been spent on mining, 101 LISK DAPPS could have been funded with >$1 000 000 each. (In return the LISK ecosystem is developed and they could even give income they receive to LISK holders in return for the initial funding, the possibilities are endless.)

In terms of competitiveness LISK would rapidly outpace ETH.

Alternatively LISK users could also vote for delegates who burn the majority of LISK they receive thereby making the inflation minuscule compared to ETH and make it much easier to overtake it with much less demand.

So LISK can obviously and may also add an ETH type DAO but it is already from the outset much more competitively designed imo.