It would help your case significantly...
If you didn't use the period 1995-2012 to try to refute the case that Silicon Valley has created few significant companies in the past decade.
That's like using The Beatles and the Doors as examples to refute an assertion that no good music has been made by the current generation.
As you say, the mere denial of venture capitalists that they've failed to create value is not evidence that it's true, but a denial 'backed up' by plumping the period from 10 years to 17 to take into account the successful few 'first wave' dot com firms does start to look like evidence.
It's also not true that a giant wave of poorly allocated VC funding to web 2.0 would cramp the tech sector. Quite the opposite in fact. The main overheads for a web 2.0 company are either hardware (from Cisco, HP and the like) or spending on services from Google, Amazon, Microsoft and the bidding up of tech sector salaries all of which serve to make the sector look very healthy.
Bilton's claim that Web 2.0 and the wider tech sector are being kept artificially inflated by a tsunami of poorly allocated VC funds which will never see a sensible return is not refuted either by harking back to 1995 nor by pointing to the boom that that artificial inflation has caused.
Quite the opposite, in fact.