Haas F1 team principal Guenther Steiner says Formula 1 is the poorer for no longer having small teams at the back of the grid which allow young drivers to take their first steps in the sport.
The HRT, Caterham and Manor teams have all ended ended up going out of business in recent seasons. And Minardi - responsible for giving breaks to Fernando Alonso and Mark Webber - was bought by Red Bull and turned into Toro Rosso at the end of 2005.
Sauber is now looking set to follow a similar path through a tie-up with Ferrari. That gives Ferrari and Red Bull junior development drivers a possible path into Formula 1, but there's little opportunity for anyone else.
"The difficulty for young drivers is they need to be in the right time at the right place," Steiner told Autosport magazine. "There is nothing else you can do for it. At the moment you cannot even buy a cockpit.
"When Minardi was around, Minardi was maybe happy to be last. That was their duty to bring drivers up," he added. "They could live with it because that was their business model. To develop drivers, that's a good business model."
Other drivers to compete for Minardi over the years include Jarno Trulli, Anthony Davidson, Giancarlo Fisichella, Justin Wilson and Stéphane Sarrazin.
Manor was the most recent team to fill that back-of-the grid gap in the market. They gave early F1 breaks to Pascal Wehrlein and Esteban Ocon, as well as future Indianapolis 500 champion Alexander Rossi.
And future Red Bull star Daniel Ricciardo got his first taste of Formula 1 at HRT in 2011, before moving to Toro Rosso the following year.
"You knew he was not going to do anything [at HRT], but it gave him experience and that's not there anymore," said Steiner.
Even Red Bull and Ferrari with junior teams or partners to give junior drivers a chance are now getting oversubscribed. Antonio Giovinazzi made his Formula 1 début for Sauber filling in for an unwell Wehrlein at the start of the season, but now faces losing out on a 2018 seat to the highly fancied Charles Leclerc.
Meanwhile Mercedes won't want Wehrlein out of Formula 1 next season, having invested a lot in developing Wehrlein.
"Between Ferrari and Mercedes, the next good guys will come out of one of them," Steiner suggested. "How they get into a seat is difficult, because Formula 1 in that respect is very difficult.
"To put Charles or Antonio straight away in a Ferrari, it's a big risk," he pointed out. "It can go well. But there are bigger chances it goes wrong, because the expectations are so high.
"Formula 2 to Formula 1, it's a different ball game. It's such a big gap, you need a little bit of learning," he explained. "You make mistakes when you're young because you don't have experience. You cannot buy experience - you need time."
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