The point is that you can suck ass for 3-5+ years, pick the consensus player at that spot, and still suck. You have to build your team as best you can and whatever pieces you can add via the draft, great.
But banking on a run of 5 years of lottery picks to magically construct a winning core is foolish to say the least.
Again with these nonsensical hypotheticals.
It isn't "magic'. It's been done, over and over again. The only teams to win a cup in the last 15 years that didn't build their core this way are Boston/STL. Sure we could try and replicate what they did, which is draft incredibly well in the lower rounds and get lucky in that way. But it's easier to do what the others did:
LA - Doughty 2nd overall, Kopitar 11th overall, Carter 10th overall. They do not win without Doughty.
Chicago - Toews 2nd overall, Kane 1st overall.
Capitals - OV 1st overall, Backstrom 4th overall
Pens - Crosby 1st overall, Malkin 2nd overall
Tampa - Hedman 2nd overall, Stamkos 1st overall
Avs - MacKinnon 1st overall, Makar 4th overall, Landeskog 2nd overall.
We are almost there with Seider at 6th, and Raymond 4th who can hopefully develop into a major difference maker. But we don't have an offensive talent like any of those teams did, and the best way to get one is through the top of the draft. It is easier to aim to be Chicago/Tampa/Pittsburgh/Colorado because that model has worked for many more teams. The Boston/St. Louis model is more difficult and requires hitting 2nd round picks out of the park, which I'm sure everyone here would agree is very difficult.
The aim isn't to be very good. It's to win the cup. And the recent evidence suggests that you are much more likely to win the cup with multiple top 3-4 lottery picks making up your core.
Sure, there are teams that have managed to squander top picks as well - Edmonton and Buffalo being the main ones. But there are many more teams that have been in constant mediocrity because they always pick 5-15: Minnesota, Calgary, Vancouver, Philadelphia, Dallas, Nashville, Carolina, Winnipeg, etc..
No method is absolute - you can fail to build a contender through the tanking method. But it's the method that has worked the most and failed the least. And that's the point.