Well obviously this is an opinions board and it's my opinion. You presumably have a different one, but I don't see any facts in your single sentence.
(I would argue) there appears to be some correlation between the degree of polarisation between the parties and the level of turnout. There was a big turnout in 1997 when people decided that they wanted to oust a tired Government, but clearly neither Tony Blair nor the various Conservative Leaders thereafter inspired people to enthusiastically support or oppose them, because there was a huge drop in turnout in the 00's compared with 1997 and the 70s and 80s when (I would argue) the parties were more polarised and the key political leaders more ideological and distinctive, if not divisive. Some would argue that Hague in 2001 and Howard in 2005 offered a strong right-wing alternative but I beg to differ. Hague arrived at the top of his party too soon and his 'Keep The Pound' mantra was very superficial, while Howard (albeit having quite a strong ideology) was a spent force and quite clearly a short-term stop gap.
Turnout at the 2017 election was the highest since 1997. Even as a Tory I think the 2017 turnout was largely driven by those inspired to support, and those equally keen to stop, Jeremy Corbyn. There was no doubt that Corbyn was offering a much more radical alternative than previous opposition leaders, and it follows that if people really believe the outcome of an election could fundamentally change their lives, they are more likely to make the effort to vote.
Of course, the most polarising debate of all in recent years was the Brexit vote, which also saw a much higher turnout than the mean for recent times.
Yes it's an argument based on subjective opinion and interpretation, but I believe people are more inspired by politics when they have very distinct choices, ideally presented by politicians with conviction. And I believe there are controlling establishment forces in this country (and many others) who see their best interests served by preventing that scenario. They would prefer the public to have the Henry Ford choice of any car painted any colour you like, so long as it's black.