Are you this stupid to compare long working hours and ability to quit any time to being literally worked to death?
They can quit any time, and then do what? Beg for a job in another factory that's just as bad?
Chains are always the most effective when they're invisible. Slavery is a crude form of a few dominating the many. Our current society looks nicer on the surface, but the underlaying mechanic is still the same: exploitation based on coercion. We have simply hidden the violence needed to keep such a system going in our property laws, ready to be used on anyone who opts out of the game yet refuses to voluntarily starve, and legitimated as defending someone else.
Of course, the problem is that such a society is fundamentally unstable: everyone hates living under someone else's thumb. Our current method of placating the masses is a promise of social mobility: if you work harder than everyone else, you can become one of the exploiters instead the exploited. But the problem with that is that it's a threat to those currently on top: for everyone who rises to the ruling class, someone else must fall, otherwise the hierarchy will flatten and erode the associated privilege. So they do everything in their power to stop social mobility and make the hierarchy steeper. The final stages are what we're seeing now: all the wealth concentrates on top, people at the bottom get heavily in debt, and finally you get a revolution when desperation reaches a critical level (or an oligarchy if those on top are smart enough to pay basic maintenance for the system their position depends on). But a revolution simply changes who's at the top, it doesn't solve the real problem - the concept of a social pyramid - so it'll just be the same system of exploitation in a shiny new package.
This is what happened to Russian revolution: Lenin and later Stalin were all too happy to use Tsar's methods to wield Tsar's power, so how could the end result be anything but Tsarism under a new name? And as Putin keeps demonstrating, the form of the system might have changed but the spirit is still quite intact.