That's relatively rare and usually happens when Labour become centerist. Conservatives have had power for 47 out of 75 years since the 2nd world war.
Labour got in for 5 years after the 2nd world war. Then you had Con for 12 years and 4 prime ministers. Then lab for 6 years, con for 4, lab for 3 - the most volatile it ever seems to have been. Then we are at Thatcher / Major for 17 years. Then Blair/Brown for 13 years. Then Con ever since. The Conservatives have complained that electoral boundaries favour Labour (even though there have been fewer years of Labour in power) and have now redrawn boundaries which should create about 10 more Conservative MPs.
Hopefully at the next election we will see some change. I'm not anti-conservative but a government like this one is insane. The "Party of Business" has done more to destroy business than any government ever. The Party of "free markets" took us out of one.
We need politicians like Rory Stewart rather than the coke guzzling journo narcissists in charge at the moment.
Let me start by saying... I did not vote for Boris
Using your figures, Labour have been in power for 28 year of my lifetime, Conservatives 47 (approximately, I am "only" 74, and at least one of the periods of power was a coalition, but, lets not quibble about that). One would have thought, in 28 years the could have done a few things to get people "on-side".
Could it be that Labour have simply failed to convince people (the electorate) that they are a better option?
Personally, I am not a tax dodging, super rich, Non-Dom, so, not really a "Boris Man", but, Labour have failed to inspire me, for most of my lifetime. In actual practice, I live in an area where they weigh the Labour votes, rather than count them, so, which ever way I vote makes little difference, in practice.