There was an article in a Hungarian newspaper "Spectrum Vilag" about how to convert Spectrum games, a lot of people started to convert speccy programs after this article had appeared (I tried also but I did not know anything about assembly and I did not have all the articles). At that time we got worse conversions.
I understand those who did not want to find all attribute bytes, it is quite hard and it was harder at that time.
Probably Total Recall should be converted from cratch.