Complete nonsense when in the last series, every test was won by the team batting first, no test (except the last one) went to a 5th day and teams couldn't even chase 200 in the final innings.
It was so bad that Joe Root got criticised for putting India in to bat first after winning a toss, in a test England lost.
Obviously, end result was England won all the tosses, and the series so it was all to do with the swing.
This is a slightly unfair recount of the last series in England.
In the first test, India had a good shot at winning and fell short by 31 runs, the crucial difference being Sam Curran's lower order runs in the 3rd innings. Not a 5 day match but a very even contest.
In the second test, England winning the toss did allow them to get the best of the overhead conditions.
I am firmly of the belief that had Bumrah been available from the start of the series and not from the 3rd test England would not have been 2-0 up.
The 3rd test India won.
The 4th test, India had a narrow first innings lead and Moeen outbowled Ashwin on a pitch that turned.
The 5th test as you pointed out went to the 5th day.
India had enough decent opportunities over the series, even without winning the toss.