Im thinking that McLaren will take till 2025 before they can challenge again for a championship.
They are getting the right building blocks in place. This year that have got a good car with some trick components. Renault has a poor car, and will probably finish 5th, behind their customer team. Renault and Mclaren are getting through the engine side of things quick enough, with all power units diverging they will get closer to the front. Id recon that there will be a Mclaren podium in the next eighteen months, if the race falls the right way.
Renault are spending big at the moment, they are spending €80m a year on equipment, tools and upgrades to bring them closer to the front, they will do so once they get the right folk in the design team and management. McLaren have done it the opposite way, management and building blocks first, then upgrades and new equipment. Racing Point are spending big at the moment, as they are spending €160m on their new building with wind tunnel, simulator and all what they need in one building. Mercedes, Ferrari and Red Bull are spending as well, Alfa are lining up a major injection in infrustructure in wind tunnel upgrades, and i am lead to believe they are getting their own driver in the loop simulator they will complete all they need. Williams are tactically spending, but they need a management rehash in the same breath. As for Haas, they are more like a race team, they need to invest in facilities, only problem is that the things they ripped out the Banbury HQ that Marussia had, they will now need, they need their act together and spend now as the resource and budget restrictions will bite as all of the budget cap will hit them as they won't be able to spend on much needed upgrades when they need, even though Dallara is they supplier. Toro Rosso are taking all the Red Bull hand me-downs, and they are investing in some areas.
Its a arms race out there in F1. Ross Brawn had it right, the regulations should have been delayed till 2021 with a budget cap in 2020. I personally, think that chassis teams need to be limited to 1,000 staff, and again, trying to get this figured out may be difficult.
McLaren are on the right track, and we will see McLaren fo further advancements next year as they have already switched, the mid pack will catch them for the rest of this year, but they may have some tracks that may just suit the car and will be enough to keep them ahead of Renault and the others. The car seems to go well at tracks that the Red Bull goes well at somehow.