The average person is NOT holding 15 whole coins... The average person is holding less than 1.
nostr:nprofile1qyv8wumn8ghj7un9d3shjuewv35kwem0duhxxmmd9uq3kamnwvaz7tmxv4jkguewdehhxarj9e3xzmny9a6x7mneqy2hwumn8ghj7un9d3shjtnyv9kh2uewd9hj7qgnwaehxw309ac82unsd3jhqct89ejhxtcpzamhxue69uhkyet5vyhxummnw3exjmpwvdsk6tcpzamhxue69uhhyetvv9ujuurjd9kkzmpwdejhgtcpr9mhxue69uhhqun9d45h2mfwwpexjmtpdshxuet59uq3uamnwvaz7tmxv4jkguewdehhxarj9e3xzmny9akxzmn89ae82qgawaehxw309a3x7um5wghxy6t5vdhkjmn50phkkmewvdhk6tcpr9mhxue69uhkzafwwp6hyurvv4ex2mrp0yhxxmmd9uqzqxvfqd89dw8kqmrjfaz6zt8gfggcg93p4tm3s2slv4jrszuugfmtl3rhfq has some videos about setting up multi-sig that are a good introduction. It really isn't hard to do with either Nunchuk or Sparrow wallet. Just need a few separate hardware wallets.
The hardest part is having separate locations where you can store them and each of their seed backups geographically separated.