There's a lot of talk about inflation and its causes. Is it corporate greed? Supply chain issues? One clear base cause of inflation less talked about is having an inflationary currency supply. Any other inflation caused by supply chain issues, corporate greed, lack of market competition, etc is just added on top of that. Fiat inflationary currency is a rather new invention in terms of the human timeline. In the US, Nixon is the start of it. Central banks aim for 2-3% inflation in "good years". The money supply expands, the portion of that supply a single dollar represents, and therefore its value, decreases. This isn't a conspiracy, it's government policy, and both parties gleefully support it because it benefits their rich donors.
Think of it: in the last 50 years, everything has gotten cheaper to produce thanks to increasing mechanization, outsourcing to cheap labor/low regulation countries, and extremely efficient supply chains. Yet so many things "cost more" than they did 50 years ago. Even basics like bread. What used to be 5c in the US in the 50s now costs $5.00. How is that the case? Shouldn't it cost less? Where is that "extra efficiency" going if not to lower prices? The answer: bread is the same value it's always been, the money has gotten less valuable. This is how they keep working class people running on a treadmill, never able to achieve economic mobility.
Inflationary currency devalues the currency you worked hard to earn by increasing the supply. It hits the middle class the worst because they have more of their net wealth in cash, often in the form of emergency funds, savings, and putting together enough money for a down payment on a home. Rich people have their money in assets which aren't harmed by currency inflation. Actually, even worse, it inflates the value of those assets! If the dollar loses value (all other things being equal), it takes more dollar to buy a share in Amazon, just like it takes more dollars to buy a loaf of bread. Poor people live hand to mouth, so their net wealth is not impacted much, but inflationary currency prevents them from saving and "moving up". If you want to identify the causes of increasing wealth disparity, the inability of people to save money and theft of value from the middle class via money supply expansion is a major one.
Really rich people are not affected as much by inflation as they take out loans to pay for their day-to-day life which is then paid back in the currency that is inflating, while it's paid with the interest they earn with company shares. Those shares are not directly hit by inflation like the loan is.
This lifestyle/procedure makes it easier to maintain your wealth compared to a regular person.
See in your example you say company value rose by 4% and inflation by 8% so they loose money, but that also means the company performed worse than before. Think of it like gold, when I have 1 ounce of gold and the dollar value sinks due to inflation, the value of my gold did not change, it's still one ounce of gold and if the gold price is not sinking for some reason, the cost/buying price of gold will most likely rise 8%, because the currency is worth 8% less but the value of gold staid the same.
Loans change their rates according to inflation. That doesn't work that way.
If I take out a $10,000 loan, which for simplicity's sake let's say is worth 10,000 loaves of bread, and next year, when payment is due, $10,000 is "worth half as much" ie I can only buy 5,000 loaves of bread with it, I only have to pay back "half the loan". I still pay the same $10k, but at the time I paid it back, I only had to trade half as much bread (my storage asset of choice) for it.
yes, this is true. no, this isn't why wages haven't kept up with productivity growth or why you must work 40 hours to sustain yourself. you have to work because profit earned must increase and paying you even one iota more than you need to be able to show up to work again tomorrow is a loss of profit. if they could make you work 80 hours a week or 160, they would in heartbeat.
thankfully, this is outlawed because labor movements of the past fought to enshrine in law a limit on how much you can be forced to work and set a minimum bar for how much they can pay you. these laws are under fire - I explore why in the rest of this reply - and will be repealed eventually if labor does not resist collectively.
however, the rate of profit always decreases on a long enough timescale because of dead labor (technology, machines, etc), inter-capitalist competition - capitalists will steal profit from each other if there's more to be had - and because infinite growth is impossible so eventually externalities will always overcome the creation of new capital.
consequently, capital accumulates in the hands of the capital-owning class - an ever-shrinking group of them, at that - and this continues until you, the worker, make so little that you cannot actually show up to work the next day - the loss of social reproduction. reproduction here doesn't only refer to progeny but also feeding, clothing, housing, etc. yourself and your family, the meeting of the basic necessities that allow you to continue working, including your health - physical and mental. capital eternally strives to reduce what it must subsidize on your behalf as ensuring you can take better care of yourself reduces profits. a capitalist that makes more profit outcompetes and drives out of business all others who choose to make less profit, eventually.
this is also why capitalism has cyclical recessions, a fact predicted in the 1870s and termed crises of capitalism, when capital has accumulated in too few hands, profit can no longer be made, and workers struggle to feed themselves. you're just noticing Marx's second law - the law of capital accumulation.