We'll see, because the summer break is still too long to wait, the changes are likely to occur if Gyokeres performs more convincingly and can present the Portugal league and Cup trophies for this year.
I think, why are Sporting lowering their prices, because Gyokeres' age is getting old. Sporting won't experience losses when they put a high price on the market.
The big clubs are not only concerned with how many goals he scored, but investment, where a player has market value in the future.
Gyokeres performance might only stand at least 1 or 2 years, so that situation, a big club like Arsenal (who always priority the young player on the squad) will think it twice before buying "old players" like Gyokeres.