Don't know why you are talking in absolutes here. There's quite a bit of venture funding outside of the cryptocurrency space. Crunchbase shows $2B total in funding for Zurich alone (https://www.crunchbase.com/hub/zurich-startups) - don't know how that compares internationally but it's definitely something rather than nothing.

Yes, and there's also a great biotech startup & VC ecosystem.

That's an interesting claim! Is there a tax efficient way to structure a tech company in Switzerland?

Taxation doesn't look very good neither on the personal level (income tax / dividend tax / tax on deemed rental value of your property if you own a house!!!) nor the company one (corporate rate tax, high cost of personnel). They do have some good deductions and a lump sum income tax for foreigners relocating to Switzerland but it seems like you won't benefit from it unless your income is 7 times higher than your yearly rent (or deemed property rental value if you own).

Is there maybe some possible legal fiscal loophole with foreign entities?

The biggest advantage in Switzerland that I know of is no capital gains tax. So if you sell shares of your company you don't pay a tax on the sale.

Pick the right canton. There are many, with very diverse tax codes, and in the smaller ones you even get to negotiate a bit (if you are big and important enough). But of course that will mean you have to be out in the sticks.

No tax on capital gain is just the most important one for any startup... (btw you do get this tax on fictional rental value of your house, but you can deduct all loan interest which are normally higher even today with the 0.8% loan rate)