Yes, there are an incredible number of new watch companies that have popped up in the last few years, and it's not just old brands being re-born. Honestly, I think most of these re-born brands as well as many microbrand and boutique brands are cashing in to some extent on the mainstream attention given to watches in the past few years.
I don't know if cashing in though is necessarily the same thing as your reference to a cynical cash grab. In a way, any new business has as it's objective the acquisition of cash, and so I don't necessarily view them in a bad light or consider them cynical.
That being said, with the sheer number of new and resurrected brands, there is a sifting process that is advisable and that is part of the fun for a watch enthusiast. Even among those brands you list, there are some I'm more keen on/ trust more than others.
What I do thing is slightly cynical is the marketing of some brands with 'stories' which unfortunately l just don't believe. Honestly, the more a new brand trades on a story, the more I turn off to them, and sometimes the re-born brands are the worst for this.
What I do look out for with these new or reborn brands is an explanation of who is behind the project and where their watches are made - not just assembled. Openness is where these new brands can create something new and exciting, given the traditional secrecy of the big Swiss brands.