About wages, that is a huge part.
People only look at 20 or 40m paid for a transfer fee, while wages are a bigger deal.
Arthur is only at 3,5m Net per year.
Frenkie is at 12m Net.
Dembele is at 13m Net.
Coutinho was at 15-16 iirc.
That means that for 4 years we had to pay:
Arthur: 40m transfer fee, 7m gross per year for wages=68m in total for 4 years od Arthur.
Frenkie: 75m transfer+10m sign on fee+24m gross=181m for 4 years
Dembele: 145m fee+26m gross=249m for 4 years
Coutinho: 165m fee+32m gross=293m for 4 years
For Eriksen, with a 12m Net (Frenkie as a kid is earning 12m Net with 4m bonuses), we would invest:
20m fee+10m sign on fee+12m Net/24m gross
4 years in total=126m invested.
Even if we sell him in 2 years for 15m (if he flops), we would still invest 78m in two years and we would get back 15m for sale.
So, we wouldn't lose only 5-10m on him but more like 63m in two years.
People will reply: but he will return it with his displays.
But what if he fails like Coutinho, Dembele or Arda?
Then he is another 60-70m thrown down the toilet in 2 years.