Each of those actions should take no more than couple of seconds (occasionally, a couple dozen). And it can, if your phone is not lagging out after lockscreen or when trying to load an on-screen keyboard.
It can take a few seconds to switch between any of these apps, especially when there are several of them running in the background. Would a new device be faster? Sure it would. Will I buy a new device sometime in the future? Sure, when this device kicks the bucket or another device shows up which offers the same feature set (good performance (compared to current devices), good battery, waterproof and sorta-shockproof yet still looks like a normal device instead of some prop from a B-movie). Do I feel like I'm missing out on something by using a 6 year old phone? No, I do not.
In my case it's not about chasing the newest features and highest resolutions - it's about certainty of getting a quality product. I no longer want to risk getting a shitty, laggy phone, or a phone that turns into one after few months. I consider it not worth the frustration it causes in daily usage.