He probably lost interest in the mod, that's normal. I don't deny that there were big plans for Barstow IV, but maybe at that time he had the motivation to add/update the mod, but over time the interest dropped. Please, keep in mind that this is just my opinion.
Having plans for updates ≠ promises. He has a personal life, he is not obliged to sit at the computer all the time and update Barstow IV every month. Perhaps, during the period when Lucas had plans for updates, there was both motivation and interest, but over time the interest faded, so why don't you understand such trivial things? Why if someone does not update a mod, then he is immediately the worst modder? Another question, why exactly Basrtow IV? Not Picnic, not Scout, not K-Series? His other mods also do not receive content, but no one complains, why exactly Barstow IV? Also remember other mods that also had plans, but no one did them and abandoned them immediately after the release, RARELY adding new content, or only fixes. Lucas is currently thinking about leaving modding because of such a community, and I understand why. Just give the person time, don't force him to do anything, if this continues we will lose a good modder.