I agree with pops, and I’m sure I read an artical a couple of years back by Mr Betts stating with a lot of the manufacturers now offering 5 to 7 warranty it is something their strategic team has thought about, but the outcome was the “sweetspot” remains 3 years, motability already allow 4th and 5th year extension, but they are able to do this by still charging the full weekly amount to cover the lose in residual and the £1000 buffer on the vehicles is there to fall back on. I think at present a standard 4 year would result in higher AP (but if it appeases the haters and Motability makes less profit, that might be the point)
Some PCP leases do offer 4 years to make it look cheaper but overall with the deposits and final payment they recover any loses.