2-6 shouldn't have been used for DTV, they weren't good enough for analog either. Maybe if they were allowed significantly more power they would be better.
Well after the full-power non-repeater analog stations go dark in 2/09, there will be quite a bit of DTV on the VHF band - much of it presumably on channels 2-6.
The point is, the low VHF band is not a good choice for digital TV. In fact, at one point, we had a channel 1, but it was abandoned/repurposed as it was simply too awful for TV transmissions, according to some sources.
Other sources don't mention reception concerns, just a need to repurpose the spectrum.
In 1940, the FCC reassigned the 44–50 MHz area of the frequency range from television to the FM broadcast band, where it remained until being moved to its current location in 1946. Television's channel 1 frequency range was moved to 50–56 MHz.
The first post-World War II telecommunications conferences formally allocated TV frequencies in 1945–1946. In 1947, the FCC decided to reserve channel 1 for lower-power community television stations, and moved existing channel 1 stations to higher frequencies. Community stations covered smaller cities and were allowed less radiated power.
From 1945 to 1948 TV stations in the U.S. shared Channel 1 and other channels with fixed and mobile services. The FCC decided in 1948 that a primary (non-shared) allocation of the VHF radio spectrum was needed for television broadcasting.
The FCC in May 1948 formally changed the rules on TV band allocations based on propagation knowledge gained during the era of shared-user allocations. The 44-50MHz band used by Channel 1 was replaced by lower-power narrowband users.
Channel 1 was reassigned to fixed and mobile services (44-50 MHz) in order to end their former shared use of other VHF TV frequencies. Rather than renumber the TV channel table, it was decided to merely remove Channel 1 from the table.
The above came from Wikipedia but matches other things I've read at various times in the past 30 years. I've also read that public service agencies (IOW police) that had shared the radio waves with broadcast television were having problems with interference. Also, logically enough, more than a few television stations reported getting interference from the public service agencies' radios.
It's been long enough that my memory is fuzzy, but I think there was something about taxi companies' radios being in the same boat.
In short, the problem wasn't that the frequency range assigned to television channel one were unsuitable for the purpose, but that the spectrum was at the time a shared one - and becoming more crowded as time wore on. That chunk of the spectrum just happened to be the one that was reassigned for other uses (and the "other uses" were then moved out of the
rest of the frequencies being used for broadcast television).