Can someone in their forties still build a solid retirement plan from a late start?

When the options are compared, a late start reduces the benefit of early compounding, but it does not make retirement planning pointless. When the options are compared, start with the household balance sheet and cash flow so the decision is based on the money actually available after near term obligations. As part of the financial analysis, increasing savings gradually, using tax advantaged accounts appropriately, controlling investment costs, and aligning the portfolio with the actual retirement date can materially improve the outcome.