Well football changes continuously, as do tactics, defending, build-up, and most important, players - what was seen as incredible years ago would most likely not work in today's football dimension. And what has now adapted to come out of the 'ordinary' is doing so despite that all aspects of football have improved considerably since the 'old days' - 80s, 90s, 2000s. Haaland or Mbappe or Benzema doing outstandingly excellent is them doing so despite already top-notch defending, top-notch tactics, top-notch availability of statistics on players and computer-aided strategy making, top-notch player selection, health, preparation, diet and training, etc.
So given that the gap between - say - an outstandingly good Maradona, or Hagi in times where their opponents did not really stand much chance - and an outstandingly good Haaland where their opponents benefit from the best conditions the world has to offer, is now closing, you can see why Haaland's incredible things (accounting for his injury periods) do not mean the era is to blame because he is seen as good, but rather it is exactly the era that makes him good - because it is this era that determines everyone in the higher football leagues and competitions to be very good given all the conditions and facilities and training and selections and knowledge possibilities everyone has in the top-notch football teams.
It is a common argument that the greatest of past strikers would be average or slightly above-average at best in today's football world. So you cannot really compare great past players in the context of today's football, as today's footballers are a lot more different than those in the past - it may seem like nothing out of the ordinary, but that is because everyone in upper leagues reached that standard of excellency and close-to-perfection that only ever 2 or 3 teams per decade used to reach 20-30-40 years ago.
Thus to be able to achieve what Haaland does in today's football world is by no means less of what great past strikers have achieved in their times - but it is certainly (at least) an amazing proportional achievement considering how and what football looks like now. To be able to stand out when billions are used for everyone to be perfect is truly remarkable.