LONDON, Jan 22 - Passion, engineering brilliance and sheer hard work can only go so far and must be paid for. In the end, teams are always chasing the sponsorship dollar even if they manage to keep their rivals behind them on the track.Glock was paid to drive at Marussia but the team made clear in a statement that was a luxury they could no longer afford when their survival was at stake in harsh economic circumstances.TOUGH ECONOMIC CLIMATEGlock had become an anomaly on a starting grid whose lower slots are increasingly being filled by drivers bringing "budget" with them. Team principal John Booth said: "The ongoing challenges facing the industry mean that we have had to take steps to secure our long-term future. "Tough economic conditions prevail and the commercial landscape is difficult for everyone, Formula 1 teams included."Marussia, one of three new teams who were encouraged into the sport in 2010 with the promise of a budget cap and favourable terms that swiftly evaporated, have the smallest budget of any current outfit.That still translates into some R620-million a season, however, and by finishing 11th overall behind Caterham in 2012 they missed out on millions in prize money divided among the top 10 teams.The team made no secret when hiring Britain's Max Chilton, a F1 rookie in 2013, that he would need backing to secure the drive and Glock's exit will allow them to bring in much-needed cash for the second seat as well.Marussia are not alone there, with vacancies outstanding at Force India and Caterham as both teams assess a number of candidates who can boast both an FIA super-licence and substantial support.The failure of Spanish-based HRT, who had Indian Narain Karthikeyan and Chinese reserve Ma Qing Hua helping to pay the bills last year before they folded, has shown how vulnerable some teams are in a sport whose revenues were expected to exceed R17-billion in 2012. NOT SPORTAgainst that backdrop, with none of the three new teams (Marussia, Caterham, HRT) scoring a point in three seasons and others above them also feeling the squeeze, driver decisions have focused on more than just talent and experience.Glock said on Twitter in a message to Red Bull's Mark Webber: "That's the way of F1 at the moment (I) hope it will change again soon because like this it has nothing to do with sport." Other leading drivers commiserated with Glock, a veteran of 91 race starts with three podiums for Toyota.Ferrari's Felipe Massa said: "We know that many drivers know to arrive in Formula One they need to have sponsors, they need to have money, especially in the small teams. "And honestly this is not a great thing for Formula One and maybe it is part of the commercial side."PAY AS YOU GOThe "pay driver" is not a new phenomenon, and indeed some of the greatest names in F1 fell into that category when starting out.Austrian triple champion Niki Lauda, now a key part of the Mercedes management team, paid substantial sums to March for drives in Formula Two and F1 in the early 1970s.By 1974 he was racing for Ferrari and being paid handsomely for his talents.Seven-times world champion Michael Schumacher made his debut for Jordan in 1991 after cash changed hands while Venezuelan Pastor Maldonado, Mexican Sergio Perez and Russian Vitaly Petrov have all been dubbed pay drivers.Maldonado is now a race winner for Williams, Perez has replaced Lewis Hamilton at McLaren and Petrov's 11th place for Caterham in Brazil in November gave his team 10th in the championship and was worth many millions.DETRACTING FROM THE SPORTDamon Hill, the 1996 champion with Williams, is not alone in expressing concern that money may now be talking too loudly in a sport that should be an arena for the world's best drivers.Hill said: "It wouldn't work in football. If you wanted to play centre forward for Man United, you still have to be pretty good. This sport has always been complicated from that point of view and I don't know what the solution is"There will always be a need for more money when the stakes get higher because people want to be more competitive. Everybody's a pay driver on the rungs up the ladder to F1."