I wonder if you ask them about this discrepancy and how they view it. Personally, I find it weird, but wonder how they'd justify the 1.5x expense.
Having a ssalary cap on certain positions, but paying top dollar for external consultants doing the same is very very common.
As an external consultant you are - to some extent - outside the hierarchy, so the usual rules don't apply.
When companies get really big and dysunctional they start to treat their customers as if they're the bottom of the hierarchy. Which is how you get all finds of corporate outrages.
So 1.5x would be a steal in comparison.
Pure employee costs are more in the 1.2 - 1.3x range (Europe). That is 30% on top of the gross salary for employer taxes, health insurances etc.
To start: everyone pays 34.75% of mandatory social contribution, even if you are on minimum wage. Government tricks people saying the contribution is "only" 11% but charges the other 23.75% from the employer.
So if a company pays 1000 eur to "you" (remember a chunk goes straight to government and skips you, but they are still spending that to pay you) you get 652.5 euro. Or 65% roughly. And that is only the social contribution part.
The average income tax for a tech worker is around 20%. Thus you get instead 500 euro flat.
Thus a Portuguese company to hire a tech worker would literally spend the double of your taxless wages just to hire you and pay the income taxes and social contribution. Then if you factor all other potential expenses things get even sillier.
some enterprising manager realizes this, makes up a new job title (that sound important) to justify the 4x salary, and thus lead to job title inflation as other people sees such a title earning high.
It's also easier to book a high fixed cost than a high ongoing cost.
Because of lack of benefits, don't have to go through unions to fire ect.
Same reason you pay higher on a short term apartmentlease.
That is, if the company hires you, they hire you (in theory) forever. But if they contract with you, that's usually for the duration of the contract - a few months. A higher rate but for a short time is easier to justify than a slightly lower, but still high, rate forever.