Brief history of the decline:
2013: Boy Scouts ends ban on gay scouts
https://www.nytimes.com/2013/05/24/us/boy-scouts-to-admit-openly-gay-youths-as-members.html
Membership 3.03 million
https://filestore.scouting.org/filestore/annualreport/2013/324-168_WB.pdf
2015: lets in gay leaders
https://www.cnn.com/2015/07/27/us/boy-scouts-gay-leaders-feat/index.html
Membership at 2.74 million
https://filestore.scouting.org/filestore/annualreport/2015/2015_Annual_Report.pdf
2016: libs report Boy Scouts doing great after ending gay ban
https://apnews.com/article/3de59dad2ba74b8f98bd3bc9b93c9bfc
Membership at 2.714 million
https://scoutingwire.org/annual-report-2016/
2017: announces will let in girls, will allow them to obtain Eagle badge
https://www.nbcnews.com/news/us-news/boy-scouts-will-admit-girls-allow-them-earn-eagle-scout-n809836
Membership at 2.659 million
2018: changes name to scouts BSA because it now lets in girls. https://www.npr.org/sections/thetwo-way/2018/05/02/607678097/boy-scouts-changing-name-to-scouts-bsa-as-girls-welcomed-into-program
Membership at 2.499
https://ar2018.scouting.org/wp-content/uploads/2019/05/BSA-2018-AnnualReport_1.pdf
2019: girls officially start being accepted as Boy Scouts
Membership at 1.97 million
2020: membership at 1.12 million
"The Boy Scouts of America said this week that the organization would create a “diversity and inclusion” merit badge and make earning it a requirement of becoming an Eagle Scout, the highest scouting rank." https://www.nytimes.com/2020/06/17/us/boy-scouts-diversity-inclusion-eagle.html
2021: membership at 762,000
I suppose the option would be to get some like minded parents, some of the materials and to recreate the spirit of the group.
The books will still contain the survival methods and be valid, just the motivation and trust needs to be rebuilt.
When I was young some of the best times were scout camps where we would go to some wooded area on the far side of a lake from civilization and build the camp and take it all down like we were never there at the end.