Sex used to keep ones job would be rape. There's a difference between sex as a job and sex used to keep other work. It's not an 'I dislike these choices' matter, but more a 'they think there is no choice-but they're being tricked" matter.
The latter is sneaky about it these days since it's not smiled upon to fuck that underpaid secretary at the boss's whim. For that kind of rape to 'work' someone has to be in a job mind set, either going for or already in. Then the Boss, for lack of a name, builds up via commentary the negativity of the outside influences until their brain starts assuming that it needs the inside situation it's in to survive. After all, didn't the nice authority figure just point out what's wrong in your life and that being here is an excellent start to get rid of one or two issues, mmhm? They just need to check the schedule for more hours. And then get back to you. (With this huge favor that they'd like repaid that they likely won't start peeping about until you feel good and caught.) And by the way, would you like to go to the company picnic?" during the first bit o'time they up the 'friendly gradual touching' and the murmurs of commiseration - not incidentally, quite a few of those moves they seem to have stolen from the Kiddle fiddlers; much of it is the same and it does a similar number on the psych, though at a considerably different angle. And so then the boss 'turns' on you (which shouldn't be a surprise, what with the playing up of your fears, the gaslighting, the encouragement in places that shouldn't be given, oh, and the casual touching.). But see, you're still under the assumption that s/he will help with advice, or more hours or just being 'friendly', in such nasty situations, surely you need a friend...eventually, sooner rather than later, you don't know what's going on exactly but you know either silence or a yes is needed, otherwise the catastrophic hell s/he's helped build up in your head Will get you.
Since this is a gay guys board I left out some gendered specifics - they matter quite a bit on how often it occurs and to who (at least from a 'rape at work' perspective), from the lauded expectations of men to the 'what did you do to encourage' bullshit.
But the victim also needs to see the (imagined, usually gaslighted, occasionally real) 'slip ups' of their own interactions on the job (and in the world, because casual conversation is a great way to pick up particulars, makes you seem like you care & intimate enough to get under the skin in casual convo when people remember. Victims are often old enough that they need to believe that the situational/characteristics they control are bad for continued survival. Authority figures also often include personality comments of a negative nature that they certainly didn't lead with at the hiring process and it's backed by 'personal observation' often from victim's rambling into what was assumed to be a friendly ear. To cement that mindset that one needs to stay, you have to attack the individual- it's no longer just the outside you've both encouraged and built to fear, but the inside as well. That's a kicker, if you don't focus on that they might start thinking they themselves have a chance somewhere, anywhere else. you can't use fear to stay without examples of one's 'mistakes' that'll land you back outside without their 'help'. Which you're now forced to focus on, but that 'help' was never in the job description. So how do you get help if the boss confirms the outside world will eat you and you're unfit for duty elsewhere? (And here, let's be honest; by this time they'll have claimed you're not working out,you're not as good a fit as they thought you'd be, but maybe...." A squeeze of the shoulder and bye bye to your Brain. The casual touching goes straight to sex, unlike prostitution there is no agreement in place. The boss is now semi-congenial (so long as there are no 'no's) and you're stuck figuring out what the fuck just occurred in the last couple weeks.
That's not sex for services/goods. Instead you trade sex for the illusion of safety some ass built up- money is likely involved but it's really off to the side. It's the fear being taken advantage of, to turn someone around so much that they think they need your help, even that authority figure clearly isn't helping in the way he's legally obligated to via good work for pay.
There's other ways to do that too; I can think of ar least three, all nastier and considerably more blatant than the example given.
The classical definition of physical force being needed has never been correct. There is a difference between prostituting ones body of their own 'free will' (in this case, pressure from outside circumstances like bills. There isn't some plotting a bit of subconscious warfare there. While in peeonme's post there most certainly is. Rape has little to do with physical force because one of the things they do is twist your mind into the 'off' position, the 'what's going on. How the flying fuck did this occur' and you brain finds no way out....' Position.