Think of a time in the past. Say the 70s. Did everything look the same? Maybe not as converged as now, but still, if you walked into a 70s bathroom you'd be like "This is a 70s bathroom". You could probably look at most cars from the 70s and say it was a 70s style design.

Trends follow fashion and capability and regulation. Cars all look the same now because they need to achieve a certain industry wide mpg set by regulation, therefore they follow the same aerodynamic constraints, leaving the makers with the same limited room to make a difference.

Room design follows fashion. You can have whatever you like, but when you want to sell a place you need to appeal to the mass market and so you go with the current up-to-date look.

And things like AirBnBs all having succulent plants and Nespresso machines - people like plants and succulents are the easiest to care for, people like coffee and Nespresso is cheap and easy to provide.

Many things are just waiting for some technical capability. Like folding phones - we'll get a flurry of interesting designs, but if they work out then eventually they'll all converge on the design that works.