Except they don't have enough votes in the house to overcome the 250 in the senate. Lots of people seem to be missing that point.
Anutin, Prawit, and Prayut have 147 votes plus the 250 senate votes. So 397 total.
If all the other parties agree to vote together that would give them 353 votes total.
And if the democrat party goes with the current leaders that will move it another 25 votes in the wrong direction.
So the oppostion may control the house but they don't control the PM.