Ricciardo is nonetheless hopeful that he and Red Bull can profit from unusually hot weather at Silverstone in race trim.
"Not every door has closed but it is looking more and more likely that the other teams will remain with their line-ups", said Ricciardo.
"I am so grateful for the support and without you I wouldn't have been able to do it".
"Obviously if it wasn't Red Bull, [Ferrari and Mercedes are] the two most attractive options".
Red Bull will be hoping for a better time of it in two weeks when F1 returns to Germany and the Hockenheimring, where they scored a double podium back in 2016.
"You can read between the lines". Both Daniel Ricciardo and Max Verstappen struggled to keep up with the front-running pace despite running a compromised race setup.
Asked in which corners the lack of power was having the biggest impact, he said: "Turn 1, for example, and Copse, and the big problem as well is when you go through a corner which is nearly flat, then when you accelerate out of the corner our engine is just not pulling, and their engine then recovers".
"What used to be a downforce circuit is now a horsepower circuit", said Ricciardo, who was also hampered by a DRS glitch.
"When you go through Maggotts and Becketts in that area, the problem is that you brake a little bit and you go back to flat-out in Stowe, out of that corner, because you go really early on the throttle, you have a bit of a steering lock and you just lose a lot".
Red Bull boss Christian Horner admitted it was a bad day for his team - but declared the poor performance of the Renault power unit vindicates his decision to switch to Honda-supplied engines for the 2019 and 2020 seasons.
Verstappen added: "It was quite weird, because on lap one I had a brake-by-wire issue, the pedal fell to the floor in Turn 3 but then it recovered and everything was going fine after that".
Max Verstappen was unable to keep Kimi Raikkonen behind as they battled over fourth place in the closing stages of Silverstone's F1 race, despite Raikkonen making a mistake and running wide at Stowe at the final safety auto restart.
"I lost DRS between Turns 4 and 6", said Ricciardo to TV reporters after the session.