That's true, if not for inter-government department feuds, the Miles M.52 might well have been the first supersonic aircraft, after taking off under it's own (turbojet) power.
But, in the late 1950's, after a string of cancelled projects, the government decided that the UK had far too many small companies, which diluted their ability to deliver the goods as aircraft projects became more complex and expensive, as well as often wasting too much time competing with each other for Defence contracts.
So BAC and HS
were formed out of most smaller companies, Handley Page resisted so the Macmillan government froze them out, a further batch of Victor B.2s were axed and the expected order for a small transport went to HS
with the 748 modified into the Andover, rather than the more suitable Herald.
Spiteful, but it's hard to argue with the logic behind this thinking, there were still smaller players around afterwards like Shorts, Westland, Scottish Aviation and soon, Brittan-Norman.
It was in the field of military aircraft and airliners that rationalization was needed, as the industry looked nervously and with envy, at the size and resources of the US giants, the same process that the UK sought happened in France over a 15 year period, as they were a similar sized economy to the UK they clearly had the same concerns.
Really, the rationalization should have happened in the early 50's, not nearly a decade later, what mattered was keeping talented design teams together, not what company banner they were under, if a bigger company meant they were more resourced, all the better.
Of course, they then had to contend with an Air Staff that changed their minds as frequently as the weather, as well as often having eyes bigger than their wallets.
On the civil side you had the same with BOAC, such as ordering V.1000s, then deciding it's too soon for jets, then ordering 707s with the same engine.
BEA also had some funny ideas, which they wanted built, like making the Trident smaller, then bitching a few years later that is was too small!
Those three institutions did the most damage, not any overdue merging of companies.