Around 20 years ago (when only a small minority of people had satellite TV), it was becoming clear that the use of the radio spectrum was inefficient, across the whole of Europe, and that substantial change was needed to accommodate all of the new services (such as mobile phones) which were being developed. So the UK government signed up to a Europe-wide agreement to re-allocate frequencies and to use those frequencies more efficiently. As part of that agreement, the UK agreed to ensure that British terrestrial TV was fully digital by 2001 at the very latest. (So we've been in breach of that international agreement for the past decade!).
You write that "the government and TV companies push the sale of Freeview". The government has little to do with it. Freeview is promoted (unsurprisingly) by Freeview which is not really a 'system', as many people seem to perceive it, but the brandname of a company called DTV Services Ltd. That company was set up by the BBC and, perhaps surprisingly, BSkyB, along with the company which owns the transmitters (originally Crown Castle UK, now National Grid Wireless). Since then, ITV plc and Channel 4 have joined the consortium.
Those organisations and companies which make up DTV Services Ltd have put a great deal of money into developing the terrestrial TV system, so it's unsurprising that they seek to promote it!
Property developers like to add as many 'extras' as possible onto their new houses, as long as they don't add significantly to the costs of building it! So many new houses have both terrestrial aerials and satellite dishes pre-fitted, with the choice of system to be used being left to the purchaser.
Chris