and which of those would you really use? is there one with an acceptable responsive gui/frontend? i gave the old ones a try when they were new and didnt like any of them. i use invoiceninja for managing contacts,invoices and much more. does all i want. what do you use?

I'll be honest, I doubt it will. At least, not in the mainstream.

Alternatives to Salesforce already exist, and there's a reason why they're not more commonplace: most companies that use Salesforce or similar CRM platforms do so because somebody else maintains it (which is why Salesforce/Zendesk/etc are more expensive than a lot of their counterparts that don't offer such services). If they have a problem with the tools, they're paying for somebody at Salesforce to fix it for them. They don't have to pay somebody in their own company to manage the servers or learn the software, they just let Salesforce manage that.

That level of support very likely wouldn't be the case with Twenty, and companies would be expected to pay somebody internally to learn and maintain their instance of the software. There's also liability issues; if your company's customer data gets breached somehow, it's Salesforce's responsibility and not yours, so you have to take on those sorts of burdens, as well. All of this starts to get very pricey (and very risky) if a company isn't already structured in a way to handle those sorts of tasks, which is why I doubt there'll be any big shift.

I'd love to be wrong, though.