Here's the thing: not every company needs to do deep tech innovation, and not every company should.
The financiers were almost certainly correct that iRobot would make more money focusing on selling vacuum cleaners, not developing military/space robots on the side. Building fancy military and space robots is fun and cool, but if it's not producing profit or clearly leading to better consumer products that make money, then it's not the right company to be doing it. Plenty of other companies will do it better -- it makes sense to have one set of companies relying on grants and defense contracts that innovate and that do fundamental research and aren't taking investor money, and another set of companies that take lots of investor money and focus on consumer products without expensive R&D. The idea that they have to be the same companies is silly.
The real story here is not about shutting down R&D -- that makes sense. It's about whether you think the FTC/Lina Khan was right to oppose Amazon acquiring iRobot, and whether they bear any responsibility for what happened after.