Would Brazil 1970 beat Spain 2008 or Man Utd 1999? Since we can't accurately predict the results of real games, it seems irrelevant to predict the results of hypothetical ones.
I know people enjoy it, but it's not for me.
Players are being noticed much earlier now (pro training starts much much earlier, and from a wider pool of talent), and also modern players are (mostly) saints in terms of maintaining their fitness ("healthy food" based in individual medical testing, no alcohol/smoking/drugs - and tested regularly for this) - while as for the 70's players - it's full of stories of late-night partying.
It's probably not difficult to understand, by analogy to things that you might be passionate about. I have zero interest in professional sports, but it's clear to me that hypotheticals like this are a way to motivate deeper structural thinking about your perception of the quality and strategy of given teams. You already have an intimate understanding of the strengths and weaknesses of your team in the context of their modern competitors. The thought experiment of pitting them against the challenge of historical teams can easily deepen your understanding of them.
Hell, you don't even need the idea of "fun" to explain this. The concept of a thought experiment is widely, almost universally useful. I might have a blindspot due to working in research, but it's my impression that modeling hypotheticals that are impossible is a fundamental skill for creative work.
No. Spain 2008-2012 may be the best overall international team of all time. Too organized even for the front five of Brazil.
> Man Utd 1999
Yes. Good team, but a lot of things broke their way that season and they were defensively somewhat weak. Though Schmeichel was one of the first goalies to be very good with the ball at his feet, so that may give an advantage in the modern game.
I think the exercise is fun partially because it makes us ask questions about the game, how it's changed and where it's going. To answer this question you need to think about the modern tactical game, the backpass rule, how players have changed and all the other factors that make me interested in a game.
In the same way evaluating movies makes me think about the context of a movie and how it was made rather than just a pure evaluation of its "quality".
Well, there's your answer! Some people love gardening. I find it dull, hot, just generally uncomfortable work. It's a chore - no, it's a job to me if I'm being honest.
So I just let others enjoy it and I take in the visuals when their work is complete.