Paddy Lowe has been instrumental in the winning of several world championships. His arrival at Williams was expected to see a resurgence of the old days when he was there some 30 years ago. Since then, he's been at the forefront of design with titles at both McLaren and Mercedes. But at Williams, he has found himself working under severe constraints as to budget. Also, the management structure is very different to those two teams.
Last year's car was embarrassingly bad: the team scored only seven points in the whole season. Williams' website starts by saying "Williams is one of the world's leading Formula One Teams. It exists purely to race in the top echelon of motor racing, where it has been winning grands prix for more than three decades."
If only. The new car, the FW42 not only missed its planned shakedown but it was three days late for the first Barcelona test. Media criticism frequently focussed on Lowe who, as the car's principle designer, was responsible for getting it finished and out on time. He has found the creation of what is, in effect, a totally new car for 2019 a challenge on many levels, not least of which is cost and deciding who, exactly, is in charge.
At the Barcelona test he told journalists that the problems were deep seated and that to place the blame on one person would be "unwise." Lowe, now a shareholder in the team, has not been described as "dismissed" and the language used ("for personal reasons") suggests that he has made the decision. That seems to be highly unlikely. Rumours were circulating that he was increasingly isolated as the problems mounted.
Following great success with Mercedes, he moved to Williams in early 2017. The 2018 car was his first for Williams and its fundamental problems were never identified: it simply did not work as the data obtained in the factory said it would.
When the 2019 car did eventually arrive in Barcelona for testing, it looked good but it was significantly off the pace, much to the chagrin of its drivers.