The spelling is correct for American and Canadian English, but the grammar is not. Saying "people could utilize" is correct, as is "people could have utilized", but (for whatever reason, and not that it matters) "people could utilized" is never utilised (alternative British Spelling). Also, "would" is arguably better than "could" in this sentence, but it should be clear to the reader either way.
Comments
not to nitpick but there's a typo 'gimabl'. I wish 21st century people could utilized the spellchecker.
Not to nitpick but there's a typo. ;-)
I think you are wrong. Please check: http://www.merriam-webster.com/dictionary/utilize
The spelling is correct for American and Canadian English, but the grammar is not. Saying "people could utilize" is correct, as is "people could have utilized", but (for whatever reason, and not that it matters) "people could utilized" is never utilised (alternative British Spelling). Also, "would" is arguably better than "could" in this sentence, but it should be clear to the reader either way.