This was discussed in a twitter spat between Musk and ULA's CEO Tory Bruno a few years ago. Back then the go-to excuse for why other companies weren't pursuing

This was discussed in a twitter spat between Musk and ULA's CEO Tory Bruno a few years ago. Back then the go-to excuse for why other companies weren't pursuing reuse was that it'd take 10 flights to break even in terms of making up for the lost payload capacity. They claimed that since they were only launching like 10 times a year, this would make it so they don't have to produce any boosters for years, screwing things up for the assembly line. Back then SpaceX was still not as firmly established in the industry, so this was them basically claiming to know better than the "new kids". Musk countered by roughly explaining the reductions they have to take (iirc 15% payload lost for the landing fuel and 10% for the extra hardware) and explained that with their costs, they've made up for that by the 3rd launch. Of course since then megaconstellations came about and other geopolitical situations caught all the other big launch providers off guard leaving F9 as basically the only ride available with any spare launch capacity (even with Vulcan and Ariane 6 not too far off, they're fully booked for quite a while). Proving that the benefits outweigh the costs.