Saas selling, immediate or scheduled calls?

I am genuinely confused as to the best model. What do others prefer and believe works best?

I am old-school, having been selling my startups products for 25 years. So in the old days we gave out our phone number everywhere (landlines if anyone remembers those). We found phone numbers of clients and just rang them, cold. And we expected to answer if someone rang us. Many downsides and not always enjoyable, but immediate calls make doing business a live and realtime process. If the call follows an email exchange, it catches people when they are thinking about you, the lead is hot!

But these days it is all about sending a Calendly link and scheduling a call (either phone or zoom/video). And in many ways, scheduling is so much tidier and peaceful. All neatly planned. I do it and have a nice block every afternoon for calls, leaving mornings for other stuff.

But have we lost something in immediacy and urgency? We get a reply from a cold email we’d sent to a lead with “yes i’d love to learn more”, but we then spend 2 or 3 followup emails arranging a call that ends up being a week away. Surely this doesn’t work as well?