The guy doesn’t know what he is talking about.
1 The business case of a company does not depend on achieving regular engineering breakthroughs or refusing to use government money/research. Apple did not invent the GUI or smartphone, and most developments in major aerospace companies were based on military funding and research. (In any case, if he’s not impressed by vertical powered landing of orbital-class stages and developing engines with unmatched thrust-to-weight ratios, then he won’t be impressed by Red Dragon or cislunar flight. Much of SpaceX’s achievements are due to incremental improvements and the willingness to take risks by applying newer, more cost-effective techniques than their risk averse competitors.)
And SpaceX is already the cheapest launch provider, even without reuse.
2 Most rockets currently used by Russia were originally developed as ICBMs, so reuse was never a high priority. Developing rockets/rocket engines is incredibly expensive, especially if you have short production runs. This is why the former USSR has extended the production run of old designs whose development costs were paid long ago by the military. Few organisations have attempted to design an engine for reliability, long life, reusability, and redundancy. You can determine engine reliability by testing, and you could argue that new engines might be less reliable than used ones (bathtub curve) .
However, it is possible that reuse could affect reliability. It is also possible that reuse cannot be achieved economically (as was the case for the Space Shuttle.) There is an interesting question about the economics of reuse versus mass production (reuse reduces the advantages of mass production and hence the ability to offset development costs). Success is not guaranteed, but I would not bet against SpaceX achieving its goal.
3 Some people have mortgages that are only 20 percent of their gross income, that doesn’t mean it’s unimportant. And while launch costs are less significant for a one-off, high cost spacecraft like the James Webb Telescope, they make a big difference to systems that use a large number of identical satellites, like Iridium.
4 and 5 He does not understand the commercial launch sector. en.wikipedia.org/wiki/Space_launch_market_competition The US lost virtually all of this market to Europe in the 1980s due to the high cost of the Space Shuttle (and later ULA rockets) compared to Ariane; the Russians grabbed some of this market after the fall of communism; now SpaceX appears set to dominate. Lobbying and high entry costs have protected ULA from competing with SpaceX on (non-COTS) government contracts, but SpaceX has begun to win USAF and NASA contracts.
In the near term, SpaceX will never get Russian or Chinese government launches, but the Russian space sector will shrink due to the loss of commercial contracts to SpaceX. If reuse is achieved, Russia, China and Europe will have to throw money at the sector to copy SpaceX or die. The real dangers to SpaceX are Blue Origin (Jeff Bezos has much deeper pockets and can withstand heavy losses for decades) and Elon’s more grandiose plans (the ITS is an incredibly risky proposition).
And as for not disrupting the space sector, ULA has had to slash its workforce, halve its launch prices, and announce that its next rocket would be partially reusable.