My set up is Nest, Xiaomi lights, tp-link plugs, chromecast tv and audio. Works far better on Google Home ( as I would expect as Chromecast is a google product). If you develop for Google home they let you publish as an Alexa skill, go figure what platform new products will develop for first. I also have Amazon music and movies through prime, which Amazon wont let me play on my google devices ( not a problem as they are inferior to Google Music(50K of your own tracks vs 1K) and Netflix anyway). My kids have Spotify which works well on either platform ( just limited by Dots ability to tap into Chromecast audio).. I have also trialled Tidal, completely pointless streaming high res music to any of the Echo devices, however works well with chromecast audio. Adding Chromecast to you apps is simple, Amazon have chose NOT to do it as they are against competition, which is why Goggle kicked their ass, hopefully the agreement is not just to sell Google products but to better integrate them so we as consumers have choice.
Really, what makes you say this? They have just release the mini and the max. I think they were slow to react but in my opinion and I have both and have developed for both is that the google one is better. I am just away to replace my dot with a home mini. If the mini had outputs to connect to hifis and speakers (other that bluetooth) then it wouldnt even be close.
Also at Gatwick
Only in airport departure lounges I think. All other Dixon stores got renamed to Currys then Currys PC World (they're all owned by the same company) Because travellers from abroad would know the Dixons name they didn't change it to Currys, if they did change the name to Currys it would confuse passengers and they'd expect spicy oriental foods and not electronics. I always though Dixons a better name than Currys but what do I know?
Amazon's plan is to brutally beat everybody else into submission and become overlords forever. Apple and Google are the same, but in slightly descending order. I don't think support will drop, simply because there's nothing particularly special about them. They're just hardware interfaces with existing assistant app features, which are themselves generally voice interfaces with other features. Also, Smart Homes are the most immediate wave of the future and Google already has a massive head start, of all three I'd count on them by far the most in the long term. Amazon will want a huge stake in the retail side of smart homes. Apple, I don't know, I don't see where they could really go with it.