Say you've started dating someone. They tell you immediately on the first date that they want to take it slow because they're looking for someone loyal who's in it for the long term. Hey, that's cool, you can deal with that. Gotta earn the doffing of the pants.
Three dates in, the pants are still on. Subtle teasing, it's a little exhausting, maybe a little humiliating. Whatever, dinner was good.
Ten dates in, you mention you'd like to take it to the next level. Obviously you're into each other, it's pretty clear long-term is on both of your minds. They're not ready yet, that's frustrating. The dinners are getting more expensive, and your date has long since stopped splitting the check.
Twenty dates in, just dinner again. Nothing has changed. You want more, they aren't willing to give it to you, and it's always for the same reasons. You start to think they're only dating you for the dinners. For the cost of a couple of these dinners, you think to yourself, I could probably buy a prostitute.
At some point, you have to reassess the relationship. A healthy relationship involves each party putting in the effort to keep the other. Your job is no different. There's a dating period, which might be the low end of the pay scale and the responsibilities you'd expect from the position. There's the going-steady period where your pay might not have changed, but your responsibilities have increased. However, if you make it to the engagement (or god forbid the marriage) period without seeing your hard work tangibly rewarded in a way you personally feel is fair, you have to start thinking that maybe the job doesn't love you and only wants you for the expensive dinners.
There's nothing wrong with job-hopping. Pensions are reserved for people with three-letter titles starting with C. Your loyalty is for shit if they're not putting out. They're going to keep you at the lowest pay/benefits for as long as possible. It's on you and you alone to check on the average salary for your position, experience, and geographic region, and you should be doing that regularly. Never stop submitting your resume, never turn off the #opentowork badge on your LinkedIn profile.
Eventually, you'll find the one who does your body good in the long term. Until then, enjoy the one night stands, you might learn something sexy.
And remember, a twin size bed is large enough to have some fun, but not big enough for them to think they can stay the night. I'm sure there's a professional analogue to that, but I can't think of what it is at the moment.