Why such a ridiculously low number of lookup fields?

Why such a ridiculously low number of lookup fields?

Why such a ridiculously low number of lookup fields? The whole point of a data base is to efficiently store information but this is really a factor which I have found so frustrating.

It means that data may have to be input manually multiple times just to tailor fields like address fields to adapt Zoho CRM to UK conventions, on data sets which are common for multiple modules such as address information. I have used up 60% of my quota on lookup fields for the address alone.

Obviously the relationships between leads->accounts->contacts->potentials is easy enough to establish from the customisation section with using my valuable lookups. But not so simple between Invoices and Accounts as there is no opportunity to map fields between accounts and invoice as there is between leads, accounts, contacts and potentials.

Is there any other way I can include the value from a field in another module without lookup?