Any reason parameterized types not supported in ActiveRecord?

I mean they are not passed on to the database to allow for prepared statements - each query, insert, update, etc is a new query. Not only are you passing around large strings, not allowing caching of prepared statements on queries, you are also depending on the way that specific SQL is constructed between different databases that may or may not be valid. For example, trying to put a big decimal value into an integer field in a string constructed SQL will truncate on some and barf on others (where the truncation would only be done in the parameter setting).

Am I missing some conscious decision on the part of the ActiveRecord designers or would developing a patch that asked the connection if it supported parameterized SQL and then constructed it if so be acceptable?