There’s a number of reasons :
It costs more than people are (currently) willing to invest because the return on investment is seen as too risky or too far into the future (10 years from now would need a return of 1000% on investment – Cost of venture capital, compounded and with a profit margin as well)
There is no guaranteed buyer for the ‘product’ as it is uncertain what the technical limitations of the product may be. This is an invisible product with no proven history or application. Evolutionary products are safer to invest in than groundbreaking ones.
Career wise – It’s interesting, but limited number of employers willing to fund your research and development and no certain future employment makes for an uncertain career path. With a house mortgage, kids and a student loan – Not a good career move.
R&D is expensive and most companies are not confident enough about the economy to invest in the long term.
Shareholders of companies are only interested in short term profits, as are Directors who are rewarded on quarterly share performance. No quarterly profit in long term gambles.
First to market will lose their shirt, as per most entrepreneurial ventures. Second to market will learn from the first’s mistakes and gain dominant market share. Who wants to be a guaranteed loser of cash? Smarter to be the second place winner.
Lack of benefactors with $ and vision to sponsor it. Bill Gates has a mission, Elon Musk has his, Warren Buffett is too conservative and already in the Gates’ camp, the Russian oligarchs have no interest as they prefer squabbling over gas and oil profits in the here and now. Who else is left?
This is a multi billion dollar deal with no guarantees. The World economy is in trouble, as are most western / rich economies. Don’t hold your breath.