In hindsight, 70m for Hakimi was very disappointing.
But if both of them were available for the same price, nobody with a right mind would take a player with flawed skillset who played in a niche position (best in his position no doubts tho) over a well rounded striker.
Unlike Lukaku, Lautaro has no weaknesses in his games that may render him useless if the opponents can exploit it. He's strong, skillful, hardworking, good with both feet, surprising great with headers. And that's just the baseline before you get to those wonderful volleys and acrobatic kicks. This is why he's so hard to neutralise and always shows up in big matches.
On the other hand, Hakimi has a few significant flaws in his game. His ball control is average and can't seem to beat defenders in situations when he can't get to speed. He also requires a very well tailored system to shine, one that covers him in defense and allows him to push high up in the pitch. These weaknesses just mean that he may not perform as great under another coach.
So for the same price, everyone will prefer Lautaro, it was particularly obvious during this summer when both Chelsea and PSG didn't offer more than 70m for Hakimi while Spurs of all clubs were willing to go all the way to 90m for Lautaro.