A person who needs a simpler plan may be protecting their chance to participate at all.

Asking for less is often read as a lack of enthusiasm, when it is usually careful arithmetic. Someone who knows their limits is choosing the version they can actually complete rather than the ambitious one that ends with them dropping out halfway. The simpler plan is how they stay in it at all.

When someone proposes a smaller version, take it as the price of their presence rather than as reluctance, and adjust without negotiating them upward. What you get is a person who is actually there, which beats a bigger plan with a gap where they used to be.