When I was a 4th grader (in CA), we studied missions but didn’t build models. My kids did as 4th graders 25-30 years ago. I resented the way it was done because the teachers would send a note home about the project saying parents were supposed to be involved in this. My kid’s teacher can’t assign home work to me. Many parents were obviously heavily involved. Many looked like professional architectural models and some were wired with lights, moving doors, etc. I loved the shoe box, popsicle sticks, sugar cube ones that the kids had done themselves - I always made it a point to compliment those kids on their models. I’m happy to see this project ditched.
Generations of teachers have been steeped in the "Progressive Education" approaches of John Dewey et al as well as educational fads like the "multiple intelligence theory" wheedled by Howard Gardner and his friends and followers. Nowadays, we can't just assign research papers--that only engages the student's "linguistic intelligence." We have to design projects that engage his "spatial intelligence," "body-kinestetic intelligence," "interpersonal intelligence," etc. So get out the popsicle sticks and the glue.