"You are absolutely right if one is using today's rocket paradigm.

I think that our basic difference is that we are talking about different time frames. NASA's stated goal is to reduce launch costs by one order of magnitude by 2015 and by two orders of magnitude by 2040. I think they have a 50-50 chance of achieving that reduction by that date. I do think that such a reduction can be achieved by 2060 (or so). So I am really talking about the mid 21st century, when I believe an explosion of space exploration will be possible."

I think a explosion in space exploration is possible within 10 years.
Why do you think that if you give NASA enough time, it will lower launch costs? NASA so far as not lower launch cost and I see no reason it would do so. Why do you think that NASA will even exist in the next hundred years if launch costs have not been lowered? If NASA continues to fart around for the next 100 years at it's current cost it will have managed to waste 1.5 trillion dollars.

"I think you are concerned about when the first mission to Mars will take place. It may well occur long before the time frame I am talking about. In such a case the costs will be enormous and the returns (to the average citizen) minimal. Such a Mars program will then suffer the same fate as the Apollo program. The average citizen will see no return for a huge investment and the program will be canceled, even if successful landings have been achieved. Such an outcome will likely once again sour the public on space projects in general. I think the ISS is headed in this direction also. I for one would not want this to happen, and am willing to forgo a Mars mission in the first half of the century to avoid such a result."

Talking about paradigms, the current one must change in order for a govt program to sent humans to Mars. If current paradigm isn't changed then NASA won't be the first to send crew to Mars.

"Achieving launch reductions of the magnitude suggested will require totally new approaches to and thinking about launching. These same changes in paradigm will likely apply to interplanetary travel as well. Several possible alternate systems are now being researched both for launch and interplanetary travel: Tethers, Lightcraft, Sails, M2P2, and others. If even one of these pans out and can be developed into a practical system the old method of calculating fuel requirements becomes irrelevant."

None of these solve the problem of how to get to the first 50 miles up (with possible exception of lightcraft, though don't think we have the laser power to lift a significant mass to orbit and beyond. Lowering launch cost is mostly about the cost of getting something into orbit.
For example, how could you get the cost down so that it costs a million dollars per person to get into orbit?
If you look at it for this angle you don't immediately think of spending billions of dollars on buying lasers. Rockets can do this if you can get the volume and get some improvements on lowering costs.

"I would advocate not worrying so much about when and how the first mission to Mars will occur. Instead we should be concerned more with developing our technology so as to reduce the costs of space access. Don't spend 50 billion on a Mars mission. Spend 20 billion on developing launch technology. We then may get to Mars sooner and cheaper."

I would advocate that government take steps to allow more competion in launch business. Offer to buy payloads which are based on performance, x amount of money for cargo brought to ISS for instance.
Or more radical (and better as far as I'm concerned) buy water payloads.
Buying water payload is very simple and very cheap way of lower launch costs. Govt offers to buy large quantities of water in orbit at low price: a total of 100 tons at $500 per lb. [costs 200,000 times 500 equals 100 million dollars, which is insignificant cost from government prospective.] Why this would be valuable to launch companies is that it allows them to test new launch systems "proving" their reliabilty- a rocket which isn't reliabilty has little value since the payload they carry is usually more expensive than the rocket itself.
Once the government has bought this water in orbit it can then possibly turn around and "sell it". The government sells it in an unusual way- it offers it free to any company that can/will use it for purpose of converting water into rocket fuel (LH&LOX). The govt is "selling it" because they are "getting" a gas station in orbit "for free". The gas station after recieving it's free water would probably be interested in buying further water payloads. So instead of the govt continuing to pay for water payload, the gas station buys them. The govt might at this point buy the "processed water" [rocket fuel or stored energy) in order to get to Mars or wherever. Overall, it may cost the govt about 1 billion, but in less than 10 years, it could create a situation in which the ticket price to orbit was a couple million and getting to crew to Mars is something costing a few billion instead of 100's of billions.
Besides getting to Mars/Moon/wherever this would also be a big step towards developing Space Power Satellites: power is needed to split water, LH&LOX is means of making energy portable and storable, and finally the higher price for electrical energy is in orbit not on Earth and as in orbit power production matures and costs are lowered, power can then be sold to Earth surface costomers.
Etc.
-gb