> But, I wonder whether a huge corporate like Google can build such large scale projects without such criticism
Yes: they could at least develop large projects in a foundation with many other companies
> And them being invested in it, is a major reason for adoption by other parties and resulting in a successful open-source project.
...and the main source of pain when the projects are "pivoted" or just dropped due to a single company business needs, as it happened many times.
> such large projects have helped overall SW ecosystem and even startups economically.
They hugely harmed competing projects and competing companies including Mozilla, many phone OSes, many grassroots programming languages.
It's well known that google developed various projects to kill competitors or buy startups cheaply and drop the project afterwards.
There isn't an infinite pool of open source developers - far from it!
Any large corporation that drains the pool to create a competitor to already existing FLOSS projects is actively harming the ecosystem.
> being a complete walled garden and just asking to 'trust us' is much worse.
Closed source can be less harmful that fake-open source. A lot of people actively avoid closed source and fall for the latter.