No they're not at all like Lotus. The only similarity is in a racing sense as highlighted.
Well they are. Williams were once the best team in F1, Lotus were once the best team in F1. Williams are having a slow decline to midfield obscurity, Lotus had a slow decline to mid-field obscurity. Lotus went bust, Williams are hanging on.
Again, no they're not. At the most superficial of levels i.e. their current performance yes, but that's literally where the comparison ends. Categorically - Williams are
not 'hanging on'. They're a company that are turning over multiple millions of pounds per year, and making a
profit of multiple millions of pounds per year. They have diversified into other areas of both technology and energy research and development to ensure that F1 is not their only income stream meaning that they can absorb poor championship years without the company being in danger. They will not be vanishing a la Lotus at all, there is no danger whatsoever.
Lotus on the other hand were for their last decade of operations unable to even provide equal resources to both of their drivers at the same time as far back as 1985 and were hemorrhaging money and seriously operating at a loss by about 1989, with no revenue beyond F1 and sponsorship coming in at all. If they couldn't become serious contenders again they were always going to go bust in a short space of time, Williams won't.
Williams can very easily have a few bad years and still be sustainable in F1, they obviously don't want to be - they want to be competitive, but the company simply isn't in any trouble whatsoever, their situation is utterly different.
Favourite racing series: F1, Indycar, NASCAR, GP2, F3, Formula E, Trophee Andros, DTM, WTCC, BTCC, World Endurance... etc. etc.