Won’t it be easier and save a lot of money to just catch it or land it in a basket?
Scaling size, volume and mass can make huge differences to engineering calculations. Consider how easy and cheap it would be to catch a toy plastic rocket thrown towards a large net. No real problem. Now consider catching a grand piano thrown off the top of a sky scrapper. It should be possible, but it’s not going to be that easy or cheap, huge net huge supports etc and plenty of calculations.
Now imagine something more than two orders of magnitude bigger than that, that’s taller than Sydney harbor bridge and weighs in at 100+ tonnes. Easy and cheap are no longer appropriate words.
But might it be easier and or cheaper than the alternatives? It might be. But the only way to find out is to do a detailed engineering assessment. The answer that was obvious at small scale is no longer obvious at large scale.
There are many complicating factors for example:
• How safe is it compared to the alternatives? What would the FAA say and what is the risk to the SpaceX launch pad / infrastructure? (Consider the piano in the above example what would the police department and skyscraper owner have to say and how would that complicate the matter?).
• Every second the rocket engine is burning it eats hundreds of kg of propellants. How quickly can that rocket engine be turned off compared to alternative means of landing? And that is no easy calculation.
• The rocket being caught is also easily damaged being made of steel that’s only a few mm thick, how accurately can it be landed? How thick must the supports be? What mass of reinforcement is required in the area that takes the strain?
• The rocket is also landing over a huge plume of fiery rocket exhaust. How fire resistant is the catching device?
Part of the reason why it has proven so difficult to land Starship is that they need to turn the rocket from horizontal to vertical very quickly. They would still need to do that even if they were to catch it in a basket.
In summary landing in a basket will also be very difficult and cost them a lot of money. They have certainly considered it and it might even be a good idea in some circumstances (perhaps For tankers and low Earth orbit cargo Starships), but the calculations are not simple or clear cut.