I still feel it’s all got to do with expectation vs actuals.
We never really pay for actuals for anything for that matter.
If the market expects interest rates to fall to 4 percent 10 years down the line, it starts discounting that effect right now and bond prices will go up now and not when interest rates actually fall.
Just to relate it with one more example.
If somebody is paying 50 rupees per share of zomato, he is not paying for zomato performance right now. He must be expecting zomato to do exceeding well 10 years down the line. That’s how much is discounted by the market.
If you are paying for 15 years plus for your education, you are expecting your benefits to exceed the cost in future.
Making sense or am I complicating it more? 
In March 2020, gilt funds value went up because nobody expected huge cuts in the interest rates. So that was a surprise. And soon after cuts everybody knew interest rates will be increased again. And then gilt started underperforming.
