Greetings. I was in the same situation as you until about a year ago. I was actually hoping Hasbro would reissue Metroplex back in 2017 when TR Trypticon came out, but it did not happen.

has reissued Metroplex twice I believe, and the last time was in 2018. BBTS had them in stock until Feb 2019. Just as I was about to get my tax return and pull the trigger they sold out.
Fortunately an auction came up on eBay a few weeks later, I was able to get a MIB T30 for just about $200. But the TT reissue would have cost me close to $300, so I was glad.
Don't give up, and be patient. It took me a couple of years of looking before I finally was able to get one. Also understand exactly what it is you want. I was willing to pay up to $200 for a loose complete T30, but I was fortunate with what came across my path.
Everyone is different. If I were still missing Metroplex, I'd be willing to settle for a loose complete one for about $250, and a MIB (of either the hasbro or TT version) I'd be willing to pay probably $350. I know they can list for much higher. I'd pursue getting one as best as possible as opposed to waiting until *who knows when* for another release, or a new toy, which I dont think should happen for at least another 10 years.
But believe me, I know there are limits. There are a few items I've resigned to myself that I'll never own because they are next to impossible to obtain (look at my wish list), or even if they were, would probably be more than I am able to pay for them. Hindsight is a pain in the ass. I had the perfect circumstances also. If I had known BC2016 was going to be the last one. I would have taken out a couple new credit cards, got the golden ticket registration, flown my whole family to Louisville, and signed all 4 of us up for the build-a-figure class. But I digress...
Don't give up searching for your Metroplex, be diligent and patient, and hopefully you can score one.