It is a much more common problem with 2.4G radio equipment, due to the different brands usually being incompatible with each other. Whereas with a 1989 vintage Acoms 27mh set, you could easily use a 2016 'vintage' futaba 27mhz receiver. I doubt if this will follow for 2.4G equipment.
I cannot even suggest buying more expensive equipment to proof you against this happening, Spektrums DSM2 system is no longer able to be sold in transmitters, effectively making this equipment obsolete. This was imposed on them by outside sources.
The Planet system had a good run of about six years before disappearing though, which in this day and age is pretty good.
Your problem with the Tamco system and it's availability isn't confined to Tamco. The same units are sold under the names of Pulse and Core also. However, they all come out of the same factory and have all been unavailable for about three months. I do not know if they are cross compatible, as I have not had the opportunity to test two of the systems together. Maybe a fellow Mayhemer could give it a try? This would at least spread the brands of Rx that you could use.
My suggestion for a 'not too expensive' set, that should be available for a good while would be the new Futaba T2HR ( don't look at it too long, it will steal your soul!!! It is a really UGLY looking hand set. Still, you should be looking at the model, not the radio! ), it is £49.99 for a combo. It is supported by one of the biggest and longest running radio control manufacturers, so should be available for a good, long time to come.
The alternative to this would be to purchase one of the cheaper Chinese sets, with £5 to £8 spare Rx's, and stock up at point of purchase. Not my chosen choice, but a number of our club members have been purchasing the Flysky FS-16, and you know what, having looked at it, I really like it as a set. For once, it isn't a rattly piece of cheap Chinese tat. We have had two in use through 2016 and they have proved reliable. Not sure of long term availability, but for not much over sixty quid, you could buy a set and up to four spare Rx's, that should do for a few years of model building!
