I don't think setting up the wallet is the hardest part. The hardest part would be to get into a legally binding agreement with the other parties, that you depend on from now on to access your "wealth", the very situation that crypto-currencies were supposed to avert.
You can make sure they don't have enough of the keys to move your funds without your consent. Making a legally binding agreement that they have to give you access to the key they have if/when you demand it is no more complex a legal task than any other instance where you trust someone to custody something for you.
I never said it was harder. I'm merely pointing out that the proposed solution to this particular usability issue that crypto-currencies suffer from involves reverting back to a web of mutual obligations enforced by courts of justice, which entirely defeats the purpose of using a crypto-currency.
It isn't difficult to set up multisignature wallets, where you can lose some subset of the keys and still retain access to the funds. (It's not easy either, but it's not difficult, and there are companies like Casa and Unchained making it easier.)
Just like someone might keep a couple hundred dollars in their wallet/on their person, a couple percent of their wealth in a home safe, and the majority of their wealth distributed across multiple locations with various failsafes to access it, someone might keep a couple hundred bucks worth of BTC in a wallet on their phone, another percent or two of their BTC in a single-sig hardware wallet in a safe at home, and the majority of their BTC in a 3-of-5 multisig setup with only two keys at home, one in a safety deposit box, one in a trusted family member's home, and one in the custody of their attorney.