I've got to agree with Geoffc's comment. Especially the comment "Cost has always been seen from a payload capacity view".
I've worked as an Aerospace Engineer in both commercial aircraft and space launch vehicles for years and years. I cannot wrap my head around how the Falcon 9 saves money landing on its tail like it does, using all that fuel. Yes that is an impressive feat. The control systems that can do that are amazing. But is this a practical way to launch and recover your booster?
NASA estimates that 1 pound of payload costs $10,000 to put in orbit. (https://www.nasa.gov/centers/marshall/news/background/facts/astp.html).
Reducing cost savings by having a reusable launch vehicle sounds attractive, but so far hasn't been shown to work from a cost savings perspective...YET.
That doesn't mean it can't be done, someday.
The big problem is re-entry does a lot of damage and you have to refurbish your launch vehicle. There a lot of heat damage if you need to re-enter the atmosphere. However even if your booster doesn't fly that high, just the friction of flying thru the atmosphere at the necessary speeds does a lot of damage, not me mention the engine vibration and the heat to parts from the engine burn itself. T
A that cuts into the "reusable" cost savings big time. NASA's Space Shuttle NEVER became cost-effective. Granted, that was a manned spacecraft and therefore more costly and for human safety, refurbishment had to be more extensive.
But at least the space shuttle had a large payload capacity. Landing as an airplane would, by GLIDING! That's very fuel efficient. Even so, it never became cost-effective.
If the Falcon 9 is going to be cost effective, I think it would have to be recovered some other way. All that fuel used to land on its tail by thrust alone seems awfully wasteful. The reserve fuel necessary for that, and its cost in weight could instead be useful and revenue generating payload!
Parachutes do the same thing and weigh a hell of a lot less than all that fuel, even if you add in the parachute deployment system. Modern parachutes can be "flown" like a glider as well.
Makes no sense to me to recover a booster that way. Even if it lands closer to the launch pad. It looks cool. But I think that's it.
But I wouldn't say the Falcon 9 has no future. I think it does. I just think for it make money it can't land like that. Too much wasted weight and payload capacity for something that is unnecessary...on the Earth anyway.
If you are landing it someplace with little or no atmosphere, like Mars or the Moon, then YES it does make sense, because you basically can't land any other way. Still, Nasa has landed probes on Mars with parachutes (large ones) and even by bouncing (Mars rover). You can get away with the latter because Mars gravity is only 38% of the Earth's gravity. Parachutes don't really work on the Moon.
Landing the way Falcon 9 lands would make perfect sense on Mars or the Moon. In fact, the very accurate way it lands would be very useful and given the lower gravity, it would not use anywhere near the same amount of heavy fuel. But such a mission is not about recovering your vehicle, at least not that part of it.