Imagine going on foot from South Africa to Argentina. At 100 km every week, it would take 520 weeks or 10 years. The memories one would make on the way would be transformational!
Perhaps tunnels in some of these spots would be more feasible? Generally, tunnels are more expensive than bridges, but when talking about crossing open ocean where weather and waves need to be accounted for, perhaps Chunnel-like crossings would end up being safer and more practical.