Invention and Innovation are separate activities with different risks and costs.
Traditionally, invention happens with individuals or very small groups - primarily because it is a creative process and it is people who have ideas. Innovation is the process of taking an invention to market, and it requires vast resources and many different activities - hence it is essentially the province of large corporations because only they have the resources to do it.
The cost of R&D - essentially the cost of innovation, is well recorded in the accounts of large corporations, and the full costs are exposed. This is not true of invention. Most inventions come to nothing, but the wasted efforts and expenses are not recorded, except perhaps in bankruptcy proceedings!
The economics of the two processes then are essentially different. Inventors are like writers (authors) whereby a very few strike it rich, but most fail to make any meaningful return on their work. Innovators are like film or theatre production companies, they take the works of a very few authors, and then spend huge sums of money trying to create a blockbuster.
Now look at the return on investment. The Oscar winning author makes a huge return on investment and the film company makes a big profit, but as return on their enormous investment, it is far more modest.
Of course, if we factor in the total costs of all the failed authors, I would suspect the the film companies actually turn in a better ROI, and this is why they purchase the creative output of independent authors.
I suspect it is the same with technology megacorps. Don't try and invent everything 'in house' because it is much cheaper to cherry-pick from the creativity of others, and by doing so you avoid the costs of failure.