If Dibling becomes an England international then where we are today, we likely arent signing him. Where we may be tomorrow, he'd cost a fortune.
If were not able to typically sign established players today, we may find that one may slip through the cracks where top sides arent interested (for whatever reason). Then we should sign them.
If there are players that the club believes will go onto become top players (Delap) then we should try for them. If there are younger players who we think will become top players (Dibling) then we should try for them.
All within the transfer budget and with clear priorities.