Since they brought in the Fixed Term Parliament Act, which was meant to force five-year gaps between General Elections, we've had three GEs in the space of just over four years, including two called early. I admire people's faith in the idea that *this time* it'll be respected, but it's pretty clearly meaningless. I wouldn't be surprised if it were scrapped altogether.
Granted, circumstances this time around are different -- the Government has a sizeable majority -- but how many times were we reassured that the next GE would be in 2020? And then in 2022? Who's to say what will happen in the coming years that might prompt an early election?
As to the claim in the post, I wouldn't be surprised if Johnson were still feeling the effects of being close to death. I don't see how this is in any sense a criticism. He's human and he's suffered a seriously debilitating illness.