Hunter was expensively educated, and graduated from top universities. This gave him a good foundation for his early career in banking, where he was apparently successful enough, and then he did a stint in the Department of Commerce before moving on to lobbying and hedge fund management. There is no clear evidence he has seriously underperformed in his jobs. On paper at least, there really is nothing that says he has gained positions beyond his merits.
They did do an investigation into the laptop and its contents, more than one, I think. There was just nothing verifiable that provided significant evidence of corruption or misconduct.
This is the core issue: there is no good evidence Hunter Biden's career is the product of corruption. Privilege and potentially advantageous social connections almost certainly, but not foul play. Simply claiming that the lack of evidence of corruption is the result of conspiracy just isn't very useful.