Is it still possible to create cutting-edge technology with a small group, a tight budget and a garage?
Quantum computing is based of components of many small specialized company's, employing fringe process skillfully. I can build you some some BCI ( one way) with components for less than 5 euros. I don't know what supercomputing is, but if you want to rent a super computer or cluster it will be very cheap. AI has pretty much peaked and is just a general tool by now. It would be great for a simple project with high impact, if you got the right idea.
* The first path is via the garage i.e. few people coming together(either experienced or people who have no idea what they are doing) and building something they love or think others love. If they succeed, they go on to build bigger things in adjacent industries or create new industries.
* The second path is the corporate path(mostly via internal research labs). Engineers at a corporation work on a problem they or their customers are facing and then stumble upon some other solution(s) to unrelated problem to create new industries.
* The third path is via the academia where researchers spend lot of time working on unsolved or novel ideas and once they find solution to the problem, they build it themselves or license it to others.
As you can see there is still the possibility of world changing companies coming out of a garage. The only difference is the people working in the garage themselves don't know that they are building world-changing industries.
"world-changing industries" only happen in the hindsight.