I don't get it, if they want to endlessly "exploit" the characters, then why make time frames at all? Literally, just let them not indicate the years when certain events take place so as not to confuse people and not to fool themselves with time transfers.
Yes, it will be strange and incomprehensible, but it is better to let it be like this than some stupid movements of time lines back and forth, twisting everything so stupidly.
Firstly, it's not exploitation if Marvel created the characters.
Secondly, you really don't get the point. Marvel tries not to tie years to their comics as it already dates them (and believe me, you read some comics from the early to mid 90s and they're dated enough as it is).
Thirdly, the whole point of a floating timeline is that you don't need to say what year it is. It's always the present day. Hence why it's called a floating or sliding timeline. But there are problems with maintaining that.
Marvel's sliding timeline works on the idea that approximately 15 years have passed since the Fantastic Four got their powers (real world year of 1961). So we're looking at 4 years real time for every 1 year in the Marvel universe. That's fine for characters like the Fantastic Four, or Spider-man or others.
Where it starts getting messy is when characters were explicitly tied to a real world event because they were meant to embody a philosophy or belief. Examples include:
- Iron Man creating his armour in Vietnam, as an anti-Communist and pro-war character. It's why a lot of Iron Man's earliest enemies were Soviet agents and imitators.
- Amongst the X-men, Professor X had fought in the Korean War.
- Flash Thompson and James Rhodes (Anti-Venom and War Machine respectively) are Vietnam War veterans.
By their very nature, those wars and origins get very dated, very quickly, necessitating shifting the origin to a more recent conflict. For example, Tony Stark can't make his armour in Afghanistan and be an anti-Communist character if the Soviet Union has been dead for 35 years, can he?
It's easier to create a fictional area that has been host to a number of conflicts in recent decades than to keep track of who needs to their origin updated every 5 years. And it's a whole lot easier to use it to maintain the sliding timeline.