The thing is if they'd waited a few years until the technology improved we'd have had a digital terrestrial system comprised of a handful of channels that you needed an expensive box to view, a situation which would have appealed to the public even less.
Starting off with a Freeview model might not have worked either. It was difficult enough to grab decent line up of free channels for a long while, let alone in 1998
In all fairness to ONdigital/ITV Digital, they were the victims (albeit a willing one) who believed they had taken advantage of a flawed attempt by the ITC to replicate the revenue beast that had been ITV in the 1960s/70s/80s.
Granada were perhaps captured by this utopian dream; as were late-comers Carlton & Sky/BSkyB, believing it was a new 'cash cow'.
The investment in technology to supply the
DTT service simply wasn't there, and it was inferior to others on offer, especially after BSkyB left the consortium.
In 1996 I went for Analogue Cable - I lived in Stockton-on-Tees, and the provider was Comcast. There was a local perception that people with the huge Sky dishes (of the time) were chavs, and BSB squarial owners were snobs. SO I went for Cable.
I then moved to Plymouth. Obviously, many people here were chavs

so I went for Sky when I moved here and got this place in 1998 as DTT reception was dreadful, and Telewest/Eurobell hadn't even cabled the new houses (something Virgin didn't manage until last year). Within 18 months all the houses in my road had Sky mini-dishes.
(I was no longer a chav)
Both ITV Digital and NTL/Telewest
(as it was by then)
had lost the march on BSkyB, who had very deep pockets and were giving away very expensive DVB-S equipment in preparation for a long-term gain.
BSkyB played the long game. ITV Digital didn't, and frankly, I'm surprised they survived as a viable parent company ITV afterwards. They initiated bad strategies, made very bad commercial decisions, and just about lasted until now.